These holds down clamps are perfect when you need to secure work pieces on router table, drill presses or other machines. The included 1/4 20 hex head bolts are compatible with most T Track brands. The rubber tips on each end are non- marring and help to securely grip work pieces. They are made from solid anodized aluminum, are 5 1/2” long, 1” wide and 1/4” thick allowing for substantial tension to be exerted. Comes with 2 each 1/4 20 x 3” long hex head bolts and 2 each 3” T knobs.