This cool mini LED strip fits on any 36mm stack and they are configurable in Cleanflight.
Some people refer to it as a 30.5mm stack as that is center hole dimensions.
It's a simple but clever design that uses 2 x rubber o-rings to mount the LEDs.
Many x frames use a minimalist top plate and 4 standoffs on the FC stack.
These LEDs are a perfect match.
This LED board only works on 5v and programmed instructions through Cleanflight or Betaflight.