Chosfox Geonix Rev.2.5 Review | A 40% Ortholinear Low-Profile Keyboard with Vial Support
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How capable is the 4th-gen off-the-shelf low-profile ortholinear?
The Chosfox Geonix Rev.2.5 is a 40%-class low-profile keyboard featuring a 4-row × 12-column ortholinear layout.
This is an improved model in the “Geonix” series co-developed by Chosfox and Japanese designer Masro, revisiting the case structure, internal sound-dampening stack, the area around the 2U spacebar, and more compared to the previous Geonix Rev.2.
It doesn’t have a dedicated number row or function keys, but it supports the QMK-based keymap tool “Vial.”
By making use of layers, combos, Mod-Tap, and more, you can assign the functions you need to a limited number of keys.
It also supports Bluetooth and 2.4GHz connections in addition to wired USB.
Paired with its compact, lightweight body and dedicated carrying case, it’s also well-suited as a portable keyboard.
Kawamura
As an ortholinear fan, I couldn’t not buy it.
In this review, I’ll cover the actual typing feel, how usable Vial is, and key points to watch out for when moving to a 40% ortholinear layout.
Geonix Rev.2.5 was not provided; it was purchased by the Greenkeys editorial team. GreenEchoes Studio, which operates Greenkeys, may receive compensation if a contract is signed from a link in this article.
With the Geonix Rev.2.5, you can choose the case, bottom layout, keycaps, and switches.
model
Case configuration
Standard keycaps
Characteristics
Full Aluminum
Aluminum exterior
LAK
Focuses on rigidity and the feel of a metal chassis
Semi-Aluminum
Aluminum + transparent side parts
LCK
Focuses on RGB effects that extend to the sides
Colors: White / Black / Silver
Case: Full Aluminum / Semi-Aluminum
Bottom layout: Dual 1U / 2U
Keycaps: LAK profile or LCK profile
The Full Aluminum model comes standard with LAK keycaps made of PBT with dye-sublimated legends.
The Semi-Aluminum model comes standard with LCK keycaps combining transparent PC material with UV printing.Chosfox official development story
You can choose from White, Black, or Silver for each color option.
Bottom layout
Layout
Configuration
Characteristics
2U
2U spacebar × 1
Feels closer to a typical spacebar
Dual 1U
1U keys × 2
Lets you assign different functions to left and right
On the 2U model, the stabilizer structure has been revised from Rev.2.
On the Dual 1U model, you can assign separate functions to the two center keys.
However, 2U and Dual 1U are chosen at purchase and cannot coexist.
Kawamura
According to Masro, for choc v2 it was difficult to make both coexist due to the relationship between stabilizer placement and the hot-swap sockets, so the PCB had to be designed separately.
Choose from Kailh Choc V2 switches
On the official product page, you can choose from five switch types.
Typing sound volume: ★★☆☆☆ (Not that loud. Acceptable for a café-level environment)
Tone Height: Intermediate (equivalent to a typical keyswitch)
Key weight: Snappy (37gf feels light for many people)
Sense of bottoming out: clear
Key wobble: normal
Pros of the Geonix Rev.2.5
Pros of the Geonix Rev.2.5
A ready-to-buy, prebuilt low-profile small keyboard
A clean 4×12 ortholinear layout
An extremely compact chassis that feels truly 40%
Vial support enables intuitive keymap design
Selectable bottom layout
Selectable case material
Plenty of switch variations
A ready-to-buy, prebuilt low-profile small keyboard
The biggest advantage of the Geonix Rev.2.5 is that you can buy a low-profile ortholinear keyboard as a complete, finished product.
In a space where many small keyboards are hard to get outside of limited GB runs, the fact that they stock-sell an aluminum-bodied—and popular low-profile—model is a one-of-a-kind appeal.
This series has a long history: starting with the choc v1 model minipeg48, then Geonix48 (effectively Rev.1.0), evolving to Geonix Rev.2 with choc v2 switch support, and now reaching its 4th generation with Rev.2.5.
minipeg48Geonix48Geonix Rev.2
It’s a niche product line that has kept releasing over time, and it’s easy to see why it has so many fans worldwide.
A clean 4×12 ortholinear layout
When it comes to ortholinear layouts, I think OLKB Planck’s contribution is huge.
My Planck v7
Kawamura
I believe this is what pioneered the ortholinear small-keyboard genre as an off-the-shelf product. Meanwhile, OLKB has stopped selling keyboards, and the Planck has already been discontinued due to Drop’s closure.
In that context, being able to buy a so-called “Planck layout” keyboard as a retail product is significant.
Also, this logical, orderly “ortholinear layout” is easy to grasp as a way to organize your thinking.
Of course, it’s fair to point out the high switching cost, but an ortholinear layout—like a grid—can actually make positional relationships easier to use when typing.
An extremely compact chassis that feels truly 40%
The Geonix Rev.2.5 is only about 24cm tall and about 8cm wide.
In everyday terms, it’s smaller than a “Nintendo Switch2.”
Kawamura
The Switch2 is about 27cm wide and about 12cm tall.
Even in its dedicated case it stays compact, and carrying it around isn’t a hassle.
Another big plus is its light weight at about 500g—roughly the weight of a single plastic bottle.
What’s more, you can carry it even more compactly by wrapping it in a cloth like the one below.
That’s a major advantage of the Geonix.
It’s even easier if you use a camera wrapping cloth, for example.
The Geonix Rev.2.5 supports Vial, letting you change the keymap in a web app without relying on your OS.
A big benefit is that you can change your keymap intuitively in a GUI without coding it yourself.
On top of that, you don’t need a JSON file when changing keymaps, and you can intuitively set tap/hold behavior—which is essential on 40% keyboards—so you can build a flexible keymap tailored to your needs. That’s a major advantage.
Layer-tap settings that let you switch layers with a hold are easy, too.You can also set chorded presses with modifiers, or make it output a modifier depending on press duration, and more.It’s also nice that you can set the hold threshold time for hold detection without compiling.
Kawamura
I leave the center 2u open and use it as a 30% layout.
筆者の30％レイアウトキーマップ（参考）
Selectable bottom layout
The biggest change from Rev.2 to Rev.2.5 is that you can now choose the bottom row layout.
Previously, the lineup only offered the 2u spacebar model, but starting with Rev.2.5 you can also choose a dual spacebar setup with 1u × 2.
However, it’s not a shared/compatible design—so note that the “PCB is a separate model.”
Selectable case material
From Rev.2.5, you can choose between two case materials: a “Full Aluminum case” and a “Semi-Aluminum case.”
The semi-aluminum case in particular seems popular because you can enjoy the LEDs on the sides of the keyboard.
Plenty of switch variations
With the Geonix Rev.2.5, you can choose from five switch types depending on your preference.
These days, it’s nice that you can choose tactile switches too—not just linear and silent linear.
Kawamura
The travel is a bit deep, but if you’re pairing it with the transparent LCK profile keycaps, the Crystal switches are also a good choice. You can enjoy flashy RGB lighting.
It’s a shame that some markings are stickers rather than laser engraving
The case and keycap combination is fixed
Neither the included keycaps nor the optional keycaps include 1u convex keys
High switching cost
That’s the fate of special-layout keyboards.
For people used to keyboards with a normal key count and a standard staggered layout (row-staggered layout), the switching cost to an ortholinear keyboard is by no means small.
In addition, typing on small keyboards—which require a layer-based approach—takes practice and getting used to.
Needing a certain amount of practice time before reaching a practically usable level is a downside in terms of the high switching cost.
Adjusting the surrounding lighting is a bit hard to understand
The appeal of the semi-aluminum case is, above all, the case lighting that can illuminate 360 degrees around the case.
On the other hand, what Vial can control with its standard features is only the RGB lighting under the switches, and the case LED lighting patterns were implemented separately.
It also doesn’t seem to be mentioned in the official manual.
It’s a bit hard to read, but in the User section, “LG_TOG” seems to toggle on/off, “LG_MOD” changes patterns, and items like “LG＿HUE” appear to adjust the lighting color.
Kawamura
I would’ve liked a bit more explanation here.
It’s a shame that some markings are stickers rather than laser engraving
One disappointing point is that the product label sticker is slapped onto the back of the case.
With it applied like this, I think many people would probably peel it off—but in Japan, depending on compliance requirements, there are reasons you may not be allowed to remove it.
(Because the technical conformity mark and number likely need to be attached to the product, you probably shouldn’t remove it.)
Laser engraving can affect the design, so I think it would be better if they changed it to a sticker sized to fit neatly into the recessed area.
The case and keycap combination is fixed
In the current lineup, the case type and keycaps are sold as a “set,” so you can’t choose any combination you want.
Semi-aluminum case → LCK keycaps
Full aluminum case → LAK keycaps
That said, even if you don’t like the default keycaps, you can buy dedicated replacement keycaps at a relatively affordable price, so it likely won’t be a major downside.
Neither the included keycaps nor the optional keycaps include 1u convex keys
Unfortunately, it seems the space keys on the Dual 1u model are not convex keys.
Both LAK and LCK share a design similar to the standard keycaps.
It has the same design with a recessed center
For LCK/LAK keycaps, I’ve confirmed that 1u convex keys exist via the seller, Jezail Funder.
From the next production lot, I really hope they make the Dual 1u model’s spacebars convex.
The LAK keycap set I bought as a replacement. Only the 2u spacebar was convex.
As the name Rev.2.5 suggests, this isn’t a model that completely overhauls the core concept or appearance.
It’s a model that keeps Rev.2’s direction while improving the case, internal structure, 2U spacebar, keymap environment, and more.
Item
Geonix Rev.2.5
Geonix Rev.2
Layout
4×12 ortholinear
4×12 ortholinear
Key Count
Dual 1U: 48 keys 2U: equivalent to 47 keys
47 keys
Bottom layout
Dual 1U / 2U
2U only
2U stabilizer
Uses an improved stabilizer
nashi (Pyrus pyrifolia, esp. var. culta)
case (e.g. receptacle, condition, event, legal action, letter style, etc.)
Full Aluminum / Semi-Aluminum
Full Aluminum
Case shape
Tray-mount case
Tray-mount case
acoustic material
two layers
two layers
daughter board
Separate
PCB-integrated
switch
Kailh Choc V2
Kailh Choc V2
hot swap
support
support
Keymap
QMK / Vial
QMK / VIA
access method
Tri-mode model only Wired / Bluetooth / 2.4GHz
Wired model Tri-mode model (Wired / Bluetooth / 2.4GHz)
keycap
LCK / LAK
LCK
selling price
From $119
From $81
Color
White / Black / Silver
White / Black / Silver
Vial support pairs well with 40% keyboards
Rev.2 supported QMK/VIA, but Rev.2.5 explicitly states Vial support.
Beyond simple key swapping, the fact that combos and Tap Dance are easier to set in the GUI is a practical change for 40% keyboards.
Improved 2U spacebar stability
In user reviews posted on the Rev.2 product page, you can find comments pointing out wobble in the 2U spacebar.
In Rev.2.5, this area was improved by adding a stabilizer, and the Dual 1U layout was also added.
Rev.2.5 is an improved version with better typing feel and build quality
Rev.2.5 adds a 5-layer acoustic structure, changes to the case shape, a separate daughterboard, and more.
With improvements like stability while typing, typing sound, chassis feel, Vial support, Dual 1u, and the semi-aluminum case, it’s an update that should satisfy both existing fans and newcomers.
[Photo Tour] Geonix Rev.2.5 Review
Now, let’s take a look at the actual Geonix Rev.2.5.
The unit comes in a box like this.Identification sticker. This seems well managed.What was in this order. The optional keycaps come in a cylindrical case.The semi-hard case opened. The side pocket contains replacement keycaps and the USB receiver.
This time I chose the Dual 1u PCB / semi-aluminum case model.
If you choose the semi-aluminum case, it automatically comes with LCK profile keycaps.
Kawamura
Personally, I prefer the LAK profile, so I also bought LAK as an extra option. I wish you could choose here.
For the switches, I chose Crystal to prioritize a clean look.
I’m very happy with the super clean appearance.
The replacement keycaps mainly include Mac symbol keycaps used on the bottom row.
However, for some reason, an unusable 2u spacebar was also included.
This is probably a packaging issue.
Kawamura
Because the PCB isn’t shared, if you choose the Dual 1u model, there’s no way you can use keycaps of that size.
Let’s look at the exterior.
The key layout is a 4-row × 12-column ortholinear layout.
You can choose either all 1u keys or a PCB with only the center as a 2u spacebar, and each uses a separate, independent PCB.
Because it’s a 40% layout with modifier keys on both sides, it’s a relatively manageable key count even for small-keyboard beginners.
It seems the semi-aluminum case is machined aluminum only on the bottom, and machined polycarbonate only on the sides.
Kawamura
To make use of the transparency on the sides, lighting is also built into the sides. However, in the default state, control options were limited, and in my environment I could only try three modes: off, solid red, and 7-color waving. This might simply be the intended behavior.
Let’s look at the exterior.
The case shape is flat, with no tilt at all.
As you’d expect from a low-profile keyboard, the case height is about 18mm and the height to the key tops is about 25mm, making it comfortable to type without a wrist rest.
On the left side of the back of the case, there’s a Type-C port and an on/off switch.
It’s also nice that the polling rate is 1000Hz both with the USB receiver and in wired mode, so you can type with low latency.
Let’s look at the bottom.
Unlike the design Masro showed on the Vero75, it features a straight, edgy, machined-aluminum design.
The Rev.2.5 engraving is cool, too.
The only real letdown is this sticker.
Kawamura
Under Japan’s Radio Act, the technical conformity mark and certification number must be “affixed in an easily visible place” on wireless equipment, so this is still perfectly compliant. Still, it does take away from the design appeal, so I’d like to see at least a smaller sticker, for example.
Let’s look around the PCB.
The PCB is north-facing (north-facing LEDs) and uses hot-swap sockets for Kailh choc v2.
The PCB is white, and the switch plate is quite flexible; while it’s not stated officially, I suspect it’s PC (polycarbonate).
It’s a bit hard to see, but the switch plate appears to be specific to Dual 1u; meanwhile, the white sound-dampening material underneath seems to be the same as the 2u model.
As with most choc v2 switch keyboards with hot-swap sockets, when swapping keycaps it’s easy to pull the switch out together.
Kawamura
That may be unavoidable due to the structure.
From the switch plate shape, it seems to use a simple “bottom case mount” style where the bottom case and switch plate are screwed together.
It matches the structure shown in the product images, too.
Kawamura
Speaking purely from experience, bottom case mount structures where the bottom and top are connected with screws tend to feel “stiff.” But knowing that, they likely chose a PC switch plate on purpose and added multiple layers of sound-dampening material. It does have a core stiffness to the typing feel, but thanks to the switch plate choice, it’s not that bothersome. If anything, I personally prefer a typing feel with less bottom-out sink.
Let’s look at the switches.
I chose “Crystal,” which you don’t often see in the low-profile keyboard scene.
Looking into it, it seems more commonly used in arcade controllers than keyboards.
Because all parts are made of PC, it has high transparency, and since it’s factory-lubed, the smooth typing feel is a big draw.
Kawamura
Personally, I preferred an even lighter typing feel, so later I switched to Taro Icecream.
Let’s also look at the keycaps.
The keycaps use Jezail Funder’s LCK profile clear keycaps.
Because they use polycarbonate, they’re highly transparent, with a spherical design that’s recessed in the center.
The keycaps themselves have no tilt, so they work well in any setup.
The legends are UV printed. They’re adhered quite well, so they don’t seem likely to peel off.MX-compatible cross-stem type.
One slightly disappointing point was that the LCK spacebar-equivalent keys weren’t convex.
Kawamura
In fact, convex LCK keys do exist
If there’s a next production lot, I really hope they include them.
Here’s a photo after swapping to the LAK keycaps I ordered separately.
I’m using a QAZ setup, and the unused areas are fitted with LCK profile keycaps.
Here too, it was disappointing that the included keycaps only had a 2u convex, and didn’t include a 1u convex keycap for the spacebar-equivalent position.
LAK doesn’t let light through, but I like it because the cylindrical shape makes it easy to type on, personally.
It’s also nice that even when paired with LCK keycaps, it doesn’t feel that out of place.
Geonix Rev.2.5 specs overview
Item
Details
Product Name
Chosfox × Masro Geonix Rev.2.5
Layout
40% ortholinear
key layout
4 rows × 12 columns
Key Count
Dual 1U: 48 keys / 2U: equivalent to 47 keys
Supported layouts
Dual 1U / 2U spacebar
case (e.g. receptacle, condition, event, legal action, letter style, etc.)
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