The RAM adapter base includes a 1″ diameter rubber ball and inserts directly to the back of Lowrance Elite 4 and Mark-4 Fishfinders. The adapter serves as a quick release mechanism, allowing you to remove or transfer your Fishfinder in seconds. Compatible Devices: Lowrance Elite-4 Lowrance Elite-4 DSI Lowrance Elite-4 Gold Lowrance Elite-4x Lowrance Elite-4x DSI Lowrance Elite-4m Lowrance Mark-4 Material: Powder Coated Marine Grade Aluminum Ball Size: 1″ Rubber “B” Ball Size