A simple case for the 4S-21S LLT BMS https://www.lithiumbatterypcb.com/product/4s-to-22s-lithium-or-lifepo4-battery-bms-with-100a-constant-current/
A small square of semi transparent PET was added to the case with epoxy so that the LED on the BMS can be seen.
The author marked this model as their own original creation.