Heavy duty springs for more clamping pressure and longer lifeNickel plated to avoid rust and marring work piecesNickel plated to prevent rustHeavy duty vinyl tips and handles to avoid marking clamping surfaces Heavy Duty Springs for More Pressure & Longer Life. Nickel Plating Wont Rust or Mark Work Piece. Heavy duty Vinyl Tips & Handles Won/t Mark Clamping Surfaces. 4 x 5Throat Depth : 5Clamping Capacity : 4