Need a mirror to keep an eye on your 6 but have no where to mount it? That is police lingo for seeing who is behind you, if you didn't know. Use this handy bar clamp for 1" motorcycle handlebars and insert perch-mount mirror of your choice. Black coated steel. This clamp has a 19/64" (.297") mounting hole all the way through and will accept most Harley-Davidson and aftermarket motorcycle mirrors. The thickness where the mirror attaches is .850 inches thick.