Woodpeckers Knuckle Clamps provide versatile gripping with no slipping. Woodpeckers new Knuckle Clamp has seven circular pivot points that provide a wide range of positions for the clamps locking knob. These multiple lock-in points maximize your clamping capabilities, enabling you to deal with different workpiece thicknesses and shapes. This great design allows you to apply even, targeted pressure to lock down the workpiece without marring its surface.