Gator Frameworks GFW-ID-SPKR-SP; Speaker spacer bar with thread; for 1 3/8 ""and M20 subwoofer mast brackets with thread; easy grip height adjustment of the tensioning knob; height adjustable from 889 - 1524mm; with removable adapter for M20 thread; load capacity: 56.7kg; built-in safety pin; Material: steel; Weight: 1.8kg; Color: black