The Nova 6039 Cole Jaw Extension kit enlarges the capacity of the Nova 6040 Cole Jaws (#54302, sold separately) from 12'' to 15''. The extensions are machined from die-cast aluminum for precise closing, durability and long life. Holes are pre-drilled and tapped to accept the bumpers included with your Cole Jaws. Installation and removal of the extensions is simple with the included fasteners and instructions.