This set includes two pencils extenders ideal for extending the life of pencils and allowing artists to waste less material. The silver extender fits larger pencils up to 9mm in diameter, and the black extender fits standard size pencils up to 7mm in diameter. They feature a metal screw-style collar that holds pencils more firmly than a standard clutch style extender. The hollow design allows for use as a holder or protector for longer pencils.