The K&M 21366 Adjustable Subwoofer to Satellite Speaker Pole Rod is a steel mounting rod between subwoofer speakers and satellite PA speakers. K&M's unique Ring Lock mechanism features an expanding mandrel. Simply turn the mechanism to adjust for a secure fit within 35 to 37mm shaft fittings. The 21366 features an adjustable height with a locking screw and safety pin mechanism. Easily adjust the pole's height between 37.4-54" (950-1370mm).