On Stage SS7745 Adjustable Subwoofer Attachment<div style="text-align: left;"><strong>[Product Information]</strong><ul><li><span class="a-list-item"> Friction locking knob adjusts length. Security pin for added safety. </span></li><li><span class="a-list-item"> Height adjustable from 31 5/8-55 </span></li><li><span class="a-list-item"> All-steel construction </span></li><li><span class="a-list-item"> Upper Shaft Tubing: 1 3/8"Lower Shaft: Fits 1 3/8" sockets </span></li><li><span class="a-list-item"> Weight Capacity: 80 lbs. </span></li></ul></div><img src="http://ecx.images-amazon.com/images/I/21IYQx7s9bL.jpg" noproxy>