This kit provides the ultimate in comfort, vibration dampening, and adjustability for your hardtailed chopper or bobber. Single or dual compact rubber air springs available. The air spring uses a bicycle style schrader fill valve that allows the rider to easily inflate the air spring from 1psi-100psi depending on rider weight and desired firmness. This kit gives you a 2.1” length of travel comparable to a set of 3” seat springs but with better vibration damping due to the fact that there is no “metal on metal” contact. Slotted mounting holes on the 1/4” thick steel seat bracket allows universal fitment. The seat bracket is powdercoated black for durability while the weld-on frame mounting bracket is formed from one piece of steel. The frame mounting bracket is coped for perfect fitment on 1 1/8” diameter frame tubing but can easily fit 1” or 1 1/4” crossmembers as well. The frame bracket is raw finish mild steel for easy weldability.