Beatdown Outdoors Mounting Plate Boat Accessory - Square, 6in x 6in - Mount plate to your boat deck and use the 4 flange bolts to bolt your mount to the deck of the boat. This setup is great for those who like to travel or like to store your electronics inside. Compatible with all mounts. Comes with the 4 Serrated Hex Bolts The square mounting plate is typically used on aluminum boats