JBL JBLPOLE-MA Manually Adjustable Speaker Pole (Pair)

Designed for strength and durability, it's the manually adjustable JBLPOLE-MA with M20 threaded lower end

Then this is exactly what you need!  This great speaker accessory features and amazing height height adjustment collar with a "Z" knob for comfortable adjusting.  The height collar on this pole prevents overtightening and any breakage issues.  It's lightweight and fits virtually all JBL subwoofers making it a versatile accessory.