Attach your Humminbird fishfinder, gimbal bracket, or other marine electronic device to your boat's bow with Arkon's APEQUIP38MM mounting plate. APEQUIP38MM features pre-drilled holes as well as a 38mm (1.5 inch) ball for easy attachment to a compatible Arkon Robust mount shaft arm, RAM Mounts Size C shaft arm, or other compatible third-party component. Attach accessories, including batteries, CB radios, Ham radios, and audio receivers. The plate can also be used as a splitter plate. The composite plate measures 6.25 inches (156mm) long and 1.94 inches (49mm) wide. It features 24 4mm unthreaded holes that are spaced apart to provide a variety of mounting options, including multiple 4-Hole AMPS devices. The four 5mm holes in the center of the plate are also recessed in the 4-Hole AMPS pattern. (The 4-Hole AMPS pattern consists of four holes located in a rectangular pattern spaced at 30.17mm by 38.05mm measured as the center-to-center distance between holes). Use with any of Arkon's shaft arms or pedestals to mount it to your boat or other surface (pedestals and screws are not included and sold separately). Compatible with Garmin GPSmap 7x12, 7x10, 12x2, 7x08, 9x2, STRIKER 9, ECHO Map Plus 6"-7", 9", Lowrance HDS 9,12, and Lowrance HDS 7,912.