ProX X-SPAM20 Deluxe 20-inch Speaker Subwoofer Pole M20 Threaded Mount 1 3/8 In. Adapter Cap.  X-SPAM20 is convenient and makes height adjustments easy—mount one end to the top of a subwoofer with an M20 thread, and the other end mounts to a 1 3/8" speaker pocket. The pole is adjustable from 33" up to 53" in total height. It features all-steel construction with a built-in Safety Pin and an Easy-Grip Tension Knob for height adjustment.

Today, more and more pole mount subwoofers now come equipped with an M20 threaded pole mount (instead of a standard 1 3/8" socket cup). This type of screw attachment ensures no tilt or wobble. The Adjustable Speaker Pole is designed to accommodate both the modern production style of subwoofers and the original 1 3/8" pole pockets, thanks to the included threaded adapter. Its all-steel shaft telescopes to the desired height and remains securely held in place with a friction-locking knob and a captive steel security pin. The lower shaft is made of steel tubing terminated with a threaded lug, while the upper shaft is sized to fit satellite speakers with standard 1 3/8" pole mounts.