Bullet Train - 40% Low Profile Wireless V4N4G0N Mechanical Keyboard

Bullet Train — uncompromisingly compact, uncompromisingly mobile

The Bullet Train is a special keyboard in the 40% world. Designed by Upas and distributed through CannonKeys, it combines three concepts that rarely come together in a single custom build: a 40-ish% layout with dedicated numbers, low-profile switches for maximum slimness, and wireless connectivity via ZMK for mobile setups. The result is a keyboard that's only 12.75U wide but lacks nothing for gaming and coding — while remaining slim enough to fit into any backpack.

 

V4N4G0N layout — 40% with dedicated numbers 1–6

The V4N4G0N layout is a clever answer to the biggest argument against 40% keyboards: reaching numbers via layers. While classic 40% boards offload all numbers to an Fn layer, the V4N4G0N takes a middle path — the numbers 1 through 6 are dedicated in a row in the top left, while numbers 7 through 0 are still accessed via layers. The exact numbers used most often in gaming (weapon swaps, hotkeys, slot bindings) remain permanently accessible, without abandoning the minimalist character of a 40% build.

The result: a layout especially loved by gamers who don't want to give up 1–6 hotkeys but are still looking for an ultra-compact setup for travel and LAN parties.

What exactly is a 40% keyboard?

If you've never worked with a 40% keyboard, you might wonder at first sight: Where are the F-row and arrow keys? The answer: all still usable — but on layers. When you hold the Fn key, letters become arrows, other keys become F-keys, and special functions. The advantage: your hands stay in the home row, you barely have to reach. With the Bullet Train, the additional comfort comes that the most important numbers 1–6 remain available in their own dedicated row — so you lose less functionality than with a pure 40%.

Low-profile with Gateron KS-33 switches

The Bullet Train is designed for Gateron KS-33 low-profile switches — and consistently leverages their advantages:

• Significantly reduced overall height — the keyboard takes up much less space than a classic MX setup
• Faster typing feel through shorter key travel
• Improved acoustics with a clearer, more compact sound profile
• Ideal for mobile setups, since the low height saves space during transport

With only 0° typing angle, the Bullet Train sits flat by default — perfect for mobile use. Anyone preferring an angled typing position can elevate the keyboard via accessories (feet/stand).

 

Premium aluminum case with thin bezels

The case is made from CNC-machined aluminum in high-profile construction with characteristically thin bezels for a clean, modern appearance. A few special design details round out the concept:

• PC diffuser for status RGB — clean, soft display of connection status
• Triangular cutout — for attaching charms, carrying loops, or carabiners for maximum mobility
• Open-top area providing enough room to house a large battery without the keyboard becoming thicker

Two PCB options — wired or wireless

With the Bullet Train, you can choose between two PCB worlds:

• Wired hot-swap PCB with QMK — wired via USB-C, with hot-swap sockets and open-source QMK firmware. Perfect for custom configuration with the full power of the QMK ecosystem (complex macros, tap dance, combos, etc.).
• Wireless hot-swap PCB with ZMK — wireless via Bluetooth, powered by the modern ZMK firmware. Thanks to the large battery and ultra-low-power ZMK architecture, several months of battery life without RGB are easily achievable. Perfect for travel and mobile setups.

Both PCBs are hot-swappable — you can swap between different Gateron KS-33 switch variants without soldering.

Big bar or split bars — you choose your spacebar layout

The Bullet Train supports two different spacebar layouts:

• Big bar — the classic, continuous spacebar in full width. Familiar and intuitive for anyone coming from a standard keyboard.
• Split bars — split spacebar with two or three separate keys at the bottom edge. Ideal for 40% workflows because the thumb keys can be used as additional modifiers or layer triggers — a real power-user feature that significantly expands the layout.

Important to know: the spacebar stabilizers are plate-mount, so the plate is fixed to one of the two options. When ordering, you choose either big bar OR split bars — switching later would require a different plate.

Gasket mounting with FR4 plate

Inside works a gasket mount system with plate foam and silicone gaskets — for a cushioned, clean typing feel with reduced hollow sound. By default, the Bullet Train ships with an FR4 plate, which according to CannonKeys is specifically optimized for wireless signal strength (aluminum plates can dampen the signal in compact wireless builds). FR4 also delivers a slightly softer typing feel than aluminum and a medium-deep sound character.

Who is the Bullet Train for?

• Gamers who want an ultra-compact setup with dedicated numbers 1–6 for hotkeys
• Travelers & commuters who want to slip a slim, lightweight premium keyboard into their backpack
• Low-profile lovers who appreciate the typing feel of the Gateron KS-33
• 40% enthusiasts looking for a layout with slightly more functionality than classic 40%
• Wireless setup designers who want a pure ZMK Bluetooth setup with long battery life
• Custom build enthusiasts looking for a unique designer board instead of a mass-market product

Note on the 40% community

If you're new to the 40% world, the 40% Keyboard Community is a great starting point — with wiki pages on layouts, configuration, and modding as well as an active Discord community.

Note: The Bullet Train is a barebone kit. Switches and keycaps are not included and must be purchased separately — the keyboard is designed for Gateron KS-33 low-profile switches; compatible keycaps must be suitable for low-profile switches.