Universal Iron Tire Changer Machine Bead Breaker Cylinder Kits, Tire Changer Bead Breaker Cylinder Fully Assembled Seal Machine Bead Breaker for Tires, Universal Tire Changer Machine For Coats/Hunter Maximum extension length of piston rod - 28cm(11") Inner cylinder diameter - 186mm(7.3") Inner cylinder ear distance - 79MM(3.11") Diameter of screw hole. Normally, it is M14.