Seaview Removable Base For Use With Mounts With 7in x 7in BaseModel: PMRB7These new-innovative mounts save time, money, and headaches for many different types of boat owners. Designed with a self-draining waterproof base, these removable bases make removing/servicing/securing/installing high-value marine electronics easier than ever. Four captive knobs for easy and quick release without fear of loosing a knob.