attwood 828661-0 SeaSport 27/8" Marine Aluminum Seat Mount with Slider Ergonomic positive-locking handles with stainless steel components PowerLock Multi-Action handle controls both swiveling and height adjustment TwinGlide Bushing ensures smooth operation and maximum stability at any height position EZ-Lock CAM-Action makes seat removal simple When engaged, seat mount is posi-locked to the post and swivels freely