The Rapala Smart Hub Adjustable Arm is an interchangeable and adjustable support mount that you can set on any flat surface (hardware included) or onto the Track System 16 with SmartHub. Use the Adjustable Arm, which includes one SmartHub connector, to position GoPro, Aqua-Vu, or MarCum underwater video cameras or other accessories that accept a 3/4 in., 1/4-20 bolt. The Rapala SmartHub Adjustable Arm is compatible with all SmartHub accessories. Interchangeable and adjustable support mount One adjustable SmartHub connector Can connect with devices that accept a 3/4' bolt Quantity per pack: 1