A MUST HAVE — Alternative for CAT J 42083, 9S9082 and 9U-7227. Tools set for Caterpillar 3406E, C-15 and C-16. ②9U-7227 Injector Height Gauge for CAT 3406E, C-15 and C-16. FUNCTION — Great hand tool for turning over engine, Simplifies TDC valve/injection timing, makes adjusting injectors and valve lash easier.