The black On-Stage Adjustable Subwoofer/Speaker Pole with Locking Adapter is designed to place your speaker over a subwoofer with a 1-3/8" diameter pole cup. The integrated locking adapter helps mitigate the wobble associated with standard speaker poles. The weight of the upper speaker activates the adapter, which expands to fill the gap between the pole and the insert. The pole is height adjustable from 32.5 to 47" and offers a weight capacity up to 100 lb.