IRWIN Vise-Grip VIS18R 18R Locking C Clamp Regular Tip 450mm (18in) IRWIN Vise-Grip Locking C Clamps reach into places where ordinary clamps cannot be used. Fitted with regular tips they are ideal for car body work welding and sheet metal work. Hex key adjusting screw that tightens to draw materials closer together and also provides controlled release. Visegrip Irwin 18R Locking C Clamp Regular Tip. Length: 450mm (18in). Throat Depth: 250mm (10in). Capacity: 203mm (8in).