Holds harmonic balancer in place when removing or installing center bolt or Ford Taurus pulley extension. Perfect for tight clearance. No need to lock flywheel. Won't warp balancer. Services 2.5 And 3.0L V6 Duratec engines from mid 1990's to 2007, including Ford Contour And Taurus, Mercury Sable, Cougar And Mystique, Lincoln LS, Jaguar S-Type, and Mazda Tribute. 5/16” thick steel base with ½” square drive. Can use 8mm x 1.25 bolt to hold tool balancer for some application. California Prop 65 - Warning, This product contains chemicals known to the State of California to cause cancer, birth defects or other reproductive harm.