The Attwood Attwood Swivl-Eze Lock'N-Pin 3/4" Pin Base's design, which has been proven again and again over decades, prevents unintentional detachment of seat mounts, posts, and bases. The 3/4" system provides exceptional economical performance, and the patented Lock'N-Pin system is leading the way in safety. Products exceed ABYC Standard H31.6.1. Not recommended to interchange with other manufacturers' products. FEATURES: Prevents unintentional detachment of seat mounts, posts, and bases The 3/4 in. system gives you outstanding economical performance Design is proven by decades of experience Lock'N-Pin system leads the industry in safety Exceed ABYC Standard H31.6.1 Not recommended to interchange with other manufacturers' products Attwood SPECS: Model: SP-67739 Description: 7 in. x 7 in., Non-Threaded, Acetal Bushing ABYC Code: B Mounting Hole: 2 3/4 in. Depth Below Deck: 2 1/2 in.