High quality and durable steel Wolf Tooth Packwrench replacement side wrench insert for mounting and dismounting cassette and centerlock discs. The side wrench, which is supplied separately, contains magnets that hold the interchangeable inserts in place. Made of hardened steel with nickel-free nickel plating. Each insert is sold separately. Ultralight Cinch and ISIS Spline Wrench Insert - older ISIS bottom brackets or the Race Face Cinch direct mount chainring system Ultralight Cassette Lock Ring Wrench Insert - cassette lockrings and some centerlock rotor lockrings Ultralight 8mm Hex Wrench Insert - pedal removal and other 8mm hex applications Ultralight 16mm Hex Wrench Insert - Race Face Cinch aluminum spindle bolts, frame pivots, and other 16mm hex applications Ultralight 20mm Socket Insert - for the Otso Cycles Tuning Chip and other 20mm socket applications