The standard size Stern Pad is a mounting block for small to medium transducers, LED lights, live-well pumps, battery switches, fuel separators, and other devices that can be attached to a boat transom/hull. The mounting block uses an industrial grade 3M adhesive to adhere to the hull without the use of screws. The adhesive has been rigorously tested and has passed a 10 years submersion test in saltwater! The dimensions of pad are 4.5" x 3.5" x .75" with rounded corners. Note: Please use the Stern Pad Jumbo for larger 3D scanning transducers