The Wolf Tooth Pack Wrench Cinch and ISIS Spline Inserts were designed to be paired with the Pack Wrench Ultralight 1 Inch Hex and Bottom Bracket Wrench. The aluminum wrench (sold separately) has magnets that hold the inserts securely in place. Made in the USA and CNC machined from hardened steel with electroless nickel plating. Inserts are each sold separately. If you travel a lot with your bikes and are always looking for the leanest way to have everything you need to build or service a bike without packing 50 lbs of tools, these tools are for you. To help with this Wolf Tooth developed some very specific Pack Tools that are high quality but weight conscious for those that do mobile maintenance, travel with their bike, or just want one set of tools that can be thrown in when heading off to the trail. While the Pack Wrench is lightweight, we wouldn't necessarily call the inserts lightweight. We made the inserts out of steel for extra long lasting strength and durability. Wolf Tooth Pack Wrench Cinch and ISIS Spline Inserts Compatibility All inserts are designed to work with our ultralight Pack Wrench. They are 1 hex drive interface compatible. 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 And many more to come! Wolf Tooth Pack Wrench Cinch and ISIS Spline Inserts Specifications Weight: Cassette Lock Ring Wrench Insert - 31g, Cinch and ISIS Spline Wrench Insert - 56g, 8mm Hex Wrench Insert - 63g, 16mm Hex Wrench Insert - 78g, 20mm Socket Insert - 67g Material: Nickel-plated 4140 Chromoly steel Made in the USA