Mega-Beam Clamp is a low profile sliding jaw design that allows you to secure your load as close to the I-Beam as possible. The 8" model has a 3 ton rating. The two aircraft aluminum jaws are adjusted on the 3/4"-6 tpi Acme threaded shaft. The spring loaded handle locks after adjustment. Aluminum construction is half the weight of steel units and has a wider gripping range. Fastens from 2 inch to 8 inch wide I-beam flanges up to 1" thick. Center hole is 1-1/2".