From the Manufacturer of Jorgensen and Pony clamps the Adjustable 1491 3 Piece C-Clamp Set contains one each of the following: 1 inch C-Clamp (our #1410), 2 inch C-Clamp (our #1420) and 3 inch C-Clamp (our#1430). Ideal for most do-it-yourself, woodworking and household clamping projects. The #1410 opening capacity is 1 inch, throat depth is 1 inch and load limit is 400 pounds. The #1420 opening capacity is 2 Inch, throat depth is 1 inch and load limit is 400 pounds. The #1430 opening capacity is 3 Inch, throat depth is 2 Inch and load limit is 800 pounds. All the C-Clamps have zinc plated frames, screws, handles and swivels. The screw is cold drawn steel with standard threads. The handle is steel and sliding pin type. The steel swivel is securely fastened to the screw and revolves freely. The anvil is machine ground. The Chicago based Adjustable Clamp Company which was established in 1903 is the manufacturer of all Adjustable C-Clamps. The Adjustable C-Clamps are assembled with U.S. and foreign parts in our Chicago factory.