Bogen Manfrotto MA394 Low Profile Quick Release Adapter with 410PL Plate.
This is one of the best "do it yourself" camera quick release systems for top-mounted skydiving setups as well as one of the best tripod quick-release mounts for skaters.
The Bogen/Manfrotto is not only low-profile, but an accidental release is impossible. This is the Bogen/Manfrotto 394 Rapid Connect 4 Low Profile Quick Release Adapter with the 3271 quick release plate. The RC4 quick release base also includes a horizontal and vertical bubble level.
This Bogen/Manfrotto is 2 9/16" x 3 3/8". The system includes 1/4"-20 and 3/8"-16 camera screws. Hardware for mounting to a helmet is not included.