Camera adapter for gopro filters

A friend of mine has taken photography as a hobby. He had a few GoPro Hero 3 filters (which are designed to snap to part of the case that covers the lens) and wnated to be able to use them with his regular camera.
This is an extremely simple design, the round part should fit around any pocket camera's objective of 44mm diameter. The rectangular side has the size and shape of the GoPro Hero 3 lens cover, so any accesory designed to fit that should work.
The rails and nudges are made to git his