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White 21-key numpad mechanical keyboard kit, hot-swap PCB, RGB LEDs, USB-C and Bluetooth 5.1

Corn Electronics

Corn Electronics GK21S White Hot-Swap Mechanical Keyboard Kit

SKU CH-3TCN-JK88J

A 21-key numpad kit with hot-swappable Kailh sockets, Bluetooth 5.1 and USB-C dual-mode, per-key RGB, 750 mAh battery and three programmable layers

  • Key SwitchNo
  • Keyboard ColorWhite

Key Switch Type No

Keyboard Color White

  • Hot-swap Kailh sockets let you change switches without soldering
  • 32-bit MCU with 8M flash stores three programmable layers
  • Bluetooth 5.1 and Type-C give dual-mode wired or wireless use
  • South-facing RGB LEDs deliver 16.8 million colours per key
  • 750 mAh battery powers music-reactive lighting and macros

Compact Custom Keyboard Kit

The Corn Electronics GK21S is a white 21-key numpad kit built for enthusiasts who want to assemble a compact input device. It ships as a PCB with hot-swap sockets and per-key RGB lighting, so you choose the switches and keycaps that match your feel. A 32-bit MCU and 8 MB flash store three programmable layers and macro commands. Dual-mode connectivity uses a Type-C cable or Bluetooth 5.1 for wireless freedom.

Best for DIY Builders Seeking a Separate Numpad

This kit suits users who want a standalone macro pad or numpad they can wire exactly to their workflow. It is not for buyers who need a full-size keyboard with dedicated function row, navigation cluster or integrated case. It also does not serve anyone who expects pre-installed switches, keycaps or a battery — the 750 mAh cell is not included.

Hot-Swap Kailh Sockets Decide Compatibility

The single spec that determines fit is the hot-pluggable Kailh connector, which accepts three-pin and five-pin MX-style switches from Cherry, BOX, Gateron and similar families. If your preferred switches use a different mounting style, the PCB will not hold them. Plate-mount stabiliser support is also provided for larger keys.

Highlights

  • Hot-swap Kailh sockets let you change switches without soldering
  • 32-bit MCU with 8M flash stores three programmable layers
  • Bluetooth 5.1 and Type-C give dual-mode wired or wireless use
  • South-facing RGB LEDs deliver 16.8 million colours per key
  • 750 mAh battery powers music-reactive lighting and macros

Specifications

Key SwitchNo
Keyboard ColorWhite

Other versions of this model

5 more in the same range

Same family, different memory, cooler or clock — compare before you commit.

Questions about this item

How can I confirm the 32-bit MCU and 8M Flash are functioning after assembly?

Connect via Type-C USB or Bluetooth 5.1, open the configuration software, and verify the firmware version and macro layers load without error.

What components are included in the kit and which parts must be purchased separately?

The kit supplies the white PCB with hot-pluggable Kailh sockets, plate-mount stabiliser support, per-key RGB LEDs and a 750mAh battery; you must buy MX-compatible switches and keycaps separately.

Which version should I choose if I want both wired and wireless use with full RGB control?

The single GK21S kit already provides Type-C USB and Bluetooth 5.1 dual-mode connectivity plus 16.8 million colour lighting, so no additional version is required.

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