Arkon Universal Marine Electronic Fishfinder Mounting Plate Use plate to attach fishfinders and other marine accessories to your boat Also attach gimbal brackets, batteries, CB radios, Ham radios, and audio receivers Includes 4mm and 5mm unthreaded holes in 4 Hole AMPS mounting pattern 2 year limited warranty The powder-coated steel plate measures 6.75 (17mm) long, 2 (50mm) wide, and 4mm thick.