The Gaffer Grips are quick mount, multi-purpose clamps that will grab on most surfaces flat or round. They reinvent the standard spring clamp by adding strength and versatility. The Large Gaffer Grip is outfitted with a variable tension control knob and comes with a long removable baby 5/8 (16mm) pin mounted in a female baby 5/8 (16mm) receiver. If you're looking for a rapid, down and dirty way to mount a lighting fixture, the Gaffer Grips are always willing and able. The KG500511 jaws can be adjusted from 1/4 to 3-1/8 (0.63-7.93cm) and is clad in a stealthy black finish.