More and more pole mount subwoofers are hitting the market with M20 threaded pole mounts instead of the older 1-3/8" socket design. The advantage is obvious: no tilt and wobble! The SS7746 is designed for this new breed of subwoofers. Its all-steel shafts telescope from 30"-54", held tight with a friction locking knob backed up by a captive steel security pin. The lower shaft features 41 mm diameter steel tubing terminated with a zinc plated threaded lug. The upper shaft is sized to fit satellite speakers with standard 1-3/8" pole mounts.