BARFLY 4 MINI MOUNT WITH 2 COMPUTER ADAPTERS, GOPRO & DI2 BASE & 2.5MM HEX KEY
GoPro base attaches with M4x1x18mm screws and nuts, included. Once adjusted it is locked in place with a hefty M5 nut and bolt. You will have to use force to get your two-fin accessory in and out. Water may help insertion.