Jezail Funder LCK-40S & Ergo Keycap Set Review

Small keyboard fans, this is a must-see.

On September 22, 2025, Jezail Funder Japan began handling the new LCK-40S & Ergo transparent black keycap set.

The keycap set is designed for 40% layout keyboards with low-profile mechanical key switches, mainly for home-built keyboards and NiuNiu @40 /Daisy layout keyboards.

This article reviews the newly released LCK-40S & Ergo keycap kit.

LCK-40S&Ergo kits were provided by Jezail Funder Japan (LLC) for promotional purposes. GreenEchoes Studio may benefit from any contracts signed through the links provided in this article.

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Jezail Funder LCK-40S & Ergo Keycap Set Overview

• Coloring: black or clear
• Material: PC (Polycarbonate)
• Stem Shape: Cherry MX Cross Axis
• Profile: LCK profile (profile with depressed center)
• Difference in slope by row: None
• Price: 4,620 yen (tax included)

Jezail Funder LCK-40S & Ergo Keycap Set Review

Let’s take a look at the LCK keycap.

It comes in the usual paper packaging familiar to Jezail Funder.

Because the kit is designed for 40% keyboards, it has two trays and a small number of keys.

There are no function keys, as it is designed for a 40% keyboard.

It consists of two alpha keys, one centered on the 1u size and the other on a special size mod key diversified by 40% size.

It is noteworthy that there are also a number of convex ski caps.

The keycap material is polycarbonate and the printing is believed to be UV printed.

The printing is quite solid and does not seem to be likely to come off even if scratched.

There is no misalignment of the print position, and the quality is good.

Unusually for a keycap, the Alpha key legend is a small legend.

The italicized, thin line font looks beautiful and stylish.

Compare the Convex keycap with a regular keycap.

Convex is on the left and regular keycap is on the right.

It is a slight difference, but it is still very easy to type when there is a convex on the thumb key.

The molding of the cross stem is very solid and does not seem to be crushed in terms of strength.

There are molding marks, but they are not noticeable.

It is carefully finished without burrs.

Now let’s actually put it on the keyboard.

We chose NiuNiu’s @40 keyboard.

The layout is as a QAZ with 1u open in the center.

The color is black transparent, but the color of the key switch is faintly visible, which is also stylish.

Homing is dot-shaped.

It is modest, but functions perfectly well as a homing key.

From the side, you can see that it is a flat profile with no difference in slope from row to row.

The spherical shape of the keys, which are recessed toward the center of the keys, naturally guides the fingers to the center of the keys, giving them a “sucking” sensation.

The circular indentation reflects light, making it a beautiful keycap, including the reflection.

Convex keys in the thumb area are also easy to press.

Basically, as far as MOD key icons are concerned, they follow the Mac.

There is no Win key, so you may need to consider replacing it accordingly.

Summary｜Recommended for people with small keyboards

This is my review of the Jezail Funder LCK 40s & Ergo keycap kit.

Smaller low-profile mechanical keyboards are all the rage these days, but there are few keycap options.

As for keycaps for low-profile mechanical keyboards on the market, unfortunately, most of them are for full-size keyboards, and there are few options for so-called “minor size” keycaps, which are 40% or smaller.

With that said, the LCK 40s & Ergo kit is an “itchy” kit.

I would highly recommend this keycap set to small keyboard enthusiasts.

Please consider purchasing one!