A cold shoe with a hot 1/4-20 armball.
that is great for lots of things.
If you have an action camera, that is not a GoPro, then it likely has a 1/4"-20 tripod mount.
And then it will fit the top of your housing with this unit.
The KIT consists of a cold shoe armball, clamp and an armball with a 1/4"-20 stud (loose stud... you can take it out).