The Shimano Crank Tool (SCT for short) is specifically built to service the chainring lockring on Shimano single ring cranksets for 12 speed drivetrains. It features a large hex that can be used with a 1.5" or 38mm wrench or locked into a vise. The clearance hole is kept to a minimum to keep the tool engaged on the low profile lockring, minimizing the chance of damaging the tool or parts.
chain ring lockrings on Shimano 12spd mountain crank sets.
XT and Ultegra bottom brackets
Made in Bend Oregon