BT75 – 75% Wireless Soldered Tray Mount PCB with RGB underglow


Out of stock

Join Waitlist We will inform you when the product arrives in stock. Please leave your valid email address below.
SKU: bt75-solder Category: Tags: , ,



Upgrade Keyboards has worked hand in hand with Polarity Works in designing and testing the initial prototype release of the BT60, and have no tested out v2 and all new pcb’s – and we absolutely love it. It just plain works! Unplug your keyboard and live wirelessly!

Introducing the Polarity Works Common Keyboard Platform (CKP). While developing this we had one goal in mind, design the best series of wireless PCBs on the market. Starting from scratch we listened to feedback from the users of the BT60 V1, added extra features, more layouts, more sizes as well as the thinnest battery ever seen in a keyboard for near 100% case compatibility.

Based around a common core design we now have 60, 65 and 75 versions, in both hotswap and soldered. As usual our soldered variants have a huge choice in layouts and encoder support. We have also strengthened the diodes and traces to lower the chances of a soldering mishap.

A huge array of features have been added. We spent a lot of time collating everything you wanted and crammed this into the little space we had:

  • More layouts! You can now have arrow keys without a 2u left shift
  • Single color key backlighting! (solder pads for Soldered boards, SMD LEDs preinstalled on hotswap)
  • 12 LED RGB underglow modules on all models
  • Support for up to 3 separate encoders on all the 65 and 75 boards (2 on the 60)
  • Power switch in the reset well (which fails to always ON even if broken off)
  • Improved reset button that is be more reliable
  • Reset jumper (you can reset it from the top of the plate without needing to pull the keyboard apart)
  • Jumper to disable the charge led for extra stealth

We noticed that some users have had issues flashing the hotswap version onto the soldered board and vice versa. The firmware files are now common between the versions, you can even flash a 75 firmware onto the 60 and it will work!

Case compatibility to be rather challenging, especially on some 65s and 75s without a battery well, so we hunted the world for a battery slim enough to fit into almost all cases and came up empty. But we decided to create it! The FilamentPower 1200 battery has a 1200mAh capacity and comes in at the THINNEST lipo battery ever put in a keyboard at just under 1.4mm thick.  it won’t decrease your battery life, with all lighting off expect the several months you’ve come to expect from our boards.

Check out our all new ZMK firmware GUI on our website or the Polarity Works website

The zmk-config repos for these boards are available here:

Purchase Worldwide:

Additional information

Weight .45 lbs
Dimensions 13 × 4.5 × 1 in

BT65 with Filament Power Battery, BT65 with Standard Battery

Keyboard Size



There are no reviews yet.

Be the first to review “BT75 – 75% Wireless Soldered Tray Mount PCB with RGB underglow”
Join Waitlist We will inform you when the product arrives in stock. Please leave your valid email address below.