If you plan on installing or removing cassette or rotor lockrings on your bike, you'll need a lockring removal tool and Abbey Bike Tools makes a great one. The updated SL Dual Sided Crombie Tool for thru-axle equipped bikes improves upon the older model to better interface with lockrings on oversized, hollow axles.This tool combines both the Shimano/SRAM standard lockring tool on one side with a larger piloting pin to fit in 12mm thru-axles. The other end is the same Shimano/SRAM fitment, sans pilot pin, with a hole deep enough to bypass most quick-release skewer nuts. A long handle provides ample leverage while removing stubborn lock rings and the tool's long splines provide plenty of purchase on soft, aluminum lock rings. This SL version features a hollow handle making it lighter for the traveling mechanicThe Abbey Bike Works Dual Sided Crombie Tool is constructed from stainless steel and is only compatible with Shimano and SRAM cassettes and rotor lockrings. Please note that this tool isn't Campagnolo compatible like the standard, non-thru-axle Crombie.