Niuniu KB40 - 40% Custom Keyboard Kit

Niuniu KB40 — five layouts, two switch worlds, one custom build

The Niuniu KB40 is one of the most versatile 40% custom build kits on the market. Where most 40% keyboards are committed to a single layout, the KB40 gives you the choice: five different layout variants (two staggered, three ortholinear), two PCB worlds (classic MX or electrostatic capacitive EC), and seven color options with characteristic Cerakote finish. A keyboard for 40% lovers who want more than just a compact keyboard — who are looking for a thoughtful, customizable custom build experience.

What exactly is a 40% keyboard?

If you've never worked with a 40% keyboard, you might wonder at first sight: Where are the numbers, F-row, and arrow keys? The answer: all still usable — but on layers. When you hold the Fn key, letters become numbers, other keys become arrows, F-keys, and special functions. The advantage: your hands stay in the home row, you barely have to reach — after a short adjustment period, 40% becomes surprisingly efficient. Programmers, Vim users, and anyone who appreciates focused typing especially love this format.

Five layouts — staggered or ortholinear

The KB40's highlight: you choose your preferred layout from five different options:

• Staggered 1 & Staggered 2 — the classic, slightly offset key arrangements you know from normal keyboards. Familiar ergonomics, immediately intuitive to use.
• Ortholinear 3, 4 & 5 — the keys are arranged in a perfect grid, all rows exactly aligned. Ortho layouts are considered ergonomically more efficient among enthusiasts, since your fingers don't need to move diagonally — especially during long typing sessions, this can reduce wrist strain.

The layout is defined by the included plate — so you choose your preferred layout when ordering, and the KB40 ships with the matching plate. If you feel like switching, additional plates can be purchased separately.

Cerakote finish — from gunsmithing to the custom world

The KB40 features a high-quality Cerakote finish — a ceramic-based coating process originally from the high-end firearms and automotive industries. Cerakote is significantly more scratch-resistant and durable than classic anodizing, has a characteristically matte, velvety feel, and delivers particularly rich, deep color tones. We offer the following color variants:

• Pink — playful, statement-bold
• Pale Gold — warm, subtle champagne gold
• Night Black — deep, matte black
• Light Silver — cool, elegant silver
• Original — Niuniu's classic color signature
• Sage Green — soft, calming sage green
• Random Cerakote — the lottery option: you'll receive a random Cerakote color from Niuniu's repertoire, often including limited editions not available in the regular selection. Perfect for collectors and anyone who enjoys an element of surprise.

Two PCB worlds — classic MX or Topre-style EC

With the KB40, you don't just choose the layout but also the switch world. Both PCB options are fully hot-swappable:

• Wired MX Hot-Swap PCB — the classic for everyone who wants to use their preferred Cherry MX-style switches. Solder-free, ready to use, compatible with all common MX switches. Includes FR4 plate.
• Wireless MX & EC-compatible Hot-Swap PCB — the real specialty: this PCB supports both classic MX switches and electrostatic capacitive (EC) switches in Topre style. This means you can switch between modern MX switches and the characteristic soft Topre sound at will — without buying a new keyboard. Includes aluminum plate.

The wireless PCB connects via Bluetooth and USB-C wired by default. 2.4 GHz wireless is also supported by the PCB — the corresponding USB dongle, however, must be purchased separately.

Gasket mounting for cushioned typing feel

Inside, the KB40 uses a gasket mounting system with "tadpole" gaskets — small, precision-shaped silicone gaskets that softly support the plate on the case. Additionally, an O-ring dampener is included, mediating between top and bottom case. The result: a cushioned, "bouncy" typing feel with pronounced acoustics, without harsh resonances or case ping.

Bottom weight with integrated battery compartment

A clever design detail: the KB40's bottom weight simultaneously serves as the battery compartment. In the wireless variant, the lithium battery is housed inside the bottom weight — providing stable footing on the desk and using interior space efficiently, without requiring a separate battery box in the case. A detail that sets the KB40 apart from many other wireless 40% builds.

Premium aluminum case

The case is made from CNC-machined aluminum — top and bottom frame in the same Cerakote color scheme, for a seamless, monolithic appearance. The substantial aluminum provides a solid typing feel and richer acoustic resonance than plastic cases — and Cerakote rounds it out with a significantly more scratch-resistant surface than classic anodizing.

Note on the foam kit

The KB40 ships without a foam kit. If you'd like to additionally tune the sound profile (foam between PCB and plate, case foam, etc.), suitable foam material can be purchased separately or cut to size. This is a deliberate design decision — many 40% builders prefer to shape their keyboard's sound without factory foam constraints.

To the community

We'd also like to take this opportunity to introduce you to the 40% Keyboard Community — there you'll find not only a great Discord community but also lots of helpful resources in the wiki!

Who is the Niuniu KB40 for?

• 40% lovers who finally want a custom kit with real layout choice (staggered & ortho)
• Ortholinear enthusiasts who want a premium aluminum build instead of cheap hobby PCBs
• Switch collectors who want to switch between MX and Topre-style EC switches in a single keyboard
• Cerakote lovers who prefer the matte, velvety finish over classic anodizing
• Travelers & commuters who want to slip an ultra-compact, wireless-capable premium keyboard into their backpack
• Custom build enthusiasts who enjoy experimental tuning — layout swaps, switch swaps between MX/EC worlds, individual foam tuning

Note: The KB40 is a barebone kit. Switches and keycaps are not included and must be purchased separately. With the wireless variant, you'll need to decide when buying switches whether you want to use MX or EC switches. Foam kit is not included. With the wireless variant, the 2.4 GHz USB dongle must be purchased separately if desired.