Kit combines 1068 - Crank Bolt Socket - 27mm & 3998 - Benz Crankshaft Pulley Holder. Use the socket for easily breaking loose the crank bolt while holding the vibration damper. Use socket with 1/2" square drive tool. Use on Mercedes Benz M271 engines. Applications: Mercedes Benz, Nissan/Infiniti & Chrysler/Dodge/Jeep.