Releases tension on serpentine belts with a spring loaded idler pulley. Ratcheting head with freewheel position allows maximumleverage. Set ratcheting head to the middle or neutral/freewheelposition and once ximum travel point is reached simplyclick lever into place to lock the ratchet mechanism. Comeswith extension for hard-to-reach idler pulleys. This tool will work where conventional ratchets or breaker bars won't fit due to limited access. Now includes 19mm socket for Honda and Toyota applications.