All-steel shaft adjusts from 31 5/8”-55” with a friction locking knob and security pin for added security. Fits tops and subwoofers wit 1 3/8" pole mounts (Max height with security pin: 53.25"). Height adjustable from 31 5/8-55" All-steel construction Upper Shaft Tubing: 1 3/8" Lower Shaft: Fits 1 3/8" sockets Shaft length: 31 5/8"-55" Weight Capacity: 80 lbs