HDI HDUMS-MUP (Multi Use Plate) is crafted from SOLID billet aluminum and CNC machined to shape, then a thin tpu grip surface is overmolded onto the ball.  The added cross pin hole is to be used at the user's discretion. When 2 pins are used to achieve 100% locked mode, you must be sure there are no underwater obstacles that may contact the transducer pole. The MUP will slide directly into any 3" mounting track , mount to any adapter that has a 4 bolt "Rod Holder" pattern, or direct mount down with user supplied hardware.