Simple and reliable mini jig. Used for expanding grooved sockets of hinges, steering knuckles and other ball joints. 5-11.5 mm. To use, the jigs pressing pawls are installed in the groove of the joint socket and then the power screw is turned with a 17 mm wrench until the socket expands. If necessary, the socket can also be carefully hit with a hammer. The jig is made of special 42CRNO steel. Electroplated. Lubricate the power screw before use. Use safety glasses.