The Kauplus Master Harmonic Balancer Installer seat is designed to Install drive pulleys or harmonic balancers that are press-fitted onto the crankshaft, available on almost every car and light truck application. The heavy-duty 7/8" diameter forcing screw has internal threads to fit the threaded adapters, both of standard and metric sizes that offer the best complete master set covering almost every and light truck applications. Set includes threaded adapter size each of: 7/16-20, 1/2-20, 9/16-18, 5/8-18, 3/4-16,M10 x 1.5, M12 x 1.0, M12 x 1.5, M12 x 1.75, M14 x 1.5, M14 x 2.0, M16 x 1.5, M16 x 2.013. These thirteen special adapters in the right reach lengths to fit most threaded crankshaft, reduces the risk of stripping threads inside the crank or breaking crank bolts. The Harmonic Balancer Pulley Installer set Made in Taiwan with antirust plating and black oxide finish, come with a blow case for easy storage. This set is designed for professional auto mechanics if the application is not listed or if you are not surely what insert to match the crank bolt to be correct insert. Caution: Always wear safety glasses when doing automotive maintenance for prevent any personal injury or properly damage.