19mm bushed socket to prevent slippage and rounding off of the cam bolt at the end of the camshafts. Services 1980-1995 Porsche 911, 3.2L Flat 6 engine. Tool securely holds an impact socket in the center, ensuring accurate loosening of the bolt, or setting the required torque. The bushing prevents the socket from being leveraged off the bolt head, keeping it squarely in place for accurate torque during installation and removal. Use with a 1/2" drive standard breaker Bar, extension and/or torque wrench. Compare to Porsche factory tool P9191.