Two (2) 48" capacity Dubuque Clamp Works UC948 bar clamps Specifications: 1-3/8 x 7/8 in. notched bar with 1/8" thick walls; movable head has spring clutch for easy and secure adjustment; fixed head features a 1/2" acme-threaded screw and wing knob for final tightening Materials: bar made from heat-treated, extruded aluminum; movable parts made from heat-treated cast 683 aluminum; acme-threaded steel screw Design allows for single-handed operation. Clamp remains reliably straight under force -- clamp your workpiece against it to prevent misalignment. Wood glues will not react with or adhere to aluminum -- no staining on your workpiece, and easy clean-up! Made in the USA! Made in USA by Dubuque Clamp Works, these aluminum bar clamps are lightweight, extremely rigid, and easy to adjust. The heat-treated, extruded aluminum bars measure 1-3/8 x 7/8 in. and have side walls nearly 1/8 in. thick for excellent resistance to bowing and twisting. The adjustable head has a spring clutch for easy adjustment along the notched bar, and the fixed head has a 1/2-in. diameter Acme-threaded screw and wing knob for final tightening. Because these clamps remain reliably straight under clamping force, you can clamp your workpiece against them to prevent misalignment. 1000 lb. load rating. 48" clamp capacity. This set includes two (2) clamps.