Wise BM1152-986 Premier Series Flip-Flop Seat Cushion is specifically designed to install on to Wise BM1152-1B-990 Premier Series Flip-Flop Seat Base, (sold separately) Can be used anywhere in the Boat with Lots of Storage in the Base. Constructed with Marine Grade Frame System. Soft Touch UV and Mildew Treated Marine Grade Vinyl. Plush High Compression Foam Padding. T-Nut Hinged Cushion Lifts Up. Aluminum Swingback Arms included to attach upper cushion to Premier Flip-Flop Seat Base.