The SS7747 Crank-up Subwoofer Attachment Shaft from On Stage is designed to hold a subwoofer weighing up to 75 pounds at an optimal height. A hand crank adjusts the height from 30 to 42 inches, and a warning label on the lower shaft indicates maximum height. The handle of the crank folds in when not in use for a polished appearance. Additionally, a safety knob and stabilizer ring on the upper shaft afford maximum security and prevent any unwanted tumbles.