The Lock 'N Pin 3/4" System gives you outstanding economical performance. Designed to prevent unintentional detachment of seat mounts, posts, and bases, Lock 'N Pin components exceed ABYC standards. 1.77" dia. post is made of brushed aluminum. Post has non-threaded steel pin. Includes integral seat mount. 1.77" diameter. Adjusts from 14" to 17" high.