BJ10 BELT-JACK INSTANT BELT TIGHTENER Designed to set belt tension and to help align pulleys on all belt driven units including blower motors, compressors, transmissions, and automotive components. FEATURES Increases belt life Easy one hand operation Prevents motor overloading Opens to 4 1/2" to 15" with extender Eliminates crowbar use Heavy duty 3/8-16 thread Eliminates belt damage