You may use the ‘Firefly S8E’ with a 90 degree lens, (without any modification / changing the lens), directly with this kit – Secure the camera to ‘GoPro’ housing with the supplied nylon screws. The only downside you don’t have fully access to power bottom (one third its accessible) you may need to press that with something like pen.
GOPRO HUSING 5,6,7 It allows you to connect GOPRO 5,6 and 7 to your side cam.
you are not be able to use your GOPRO directly without changing the lens to 12mm or 16mm Focal,
the standard GOPRO lens bracket size is m12 x 0.35 pitch.
MUN-1 will be required to connect the GOP-II to your side cam.