JamStands Series Adjustable Subwoofer Pole. The JS-SP50 is exactly what you need for your subwoofer/satellite speaker PA system. It's adjustable in height from 31.5" to 52.5" and mounts between a subwoofer cabinet with a top mounting hole and a speaker with a bottom mounting hole (1.375" for both). The JS-SP50 features both a friction locking knob and a security pin system and is made from durable steel.SpecsHeight: 31.5” – 52.5” (800mm – 1334mm)Upper Tube Size: 1.375” (35mm)Lower Tube Size: 1.375” (35mm)Weight Rating: 110 lbs. (50 kg)Weight: 3 lbs. (1.4 kg)