CudaX DPV SK-8 compass holder.

Compass is removable using bungee cord to secure it. Pins (2 works but there is holes for 4 pins if you prefer) are used only to avoid the compass to become offset during a dive.

You need two M5 bolts. Use lock washer under each. After some tests, it won't become lose during long dives with this, so there's no need to use Loctite.