30x30 to 20x20mm adapter

Simple adapter to mount a 20x20mm PCB on top of a 30x30mm PCB.  Mostly intended for building FPV stacks.  In the photo you can see that I have mounted a 20x20mm VTX on top of a 30x30mm flight controller (on top of an ESC...).  This is unthreaded, so you will need to use nuts -- there is plenty of clearance.  Holes are sized for M3 screws.