For pulling jobs requiring an internal pull, such as pilot bearings. Set includes four collets which fit a wide range of applications. Set includes a 2-1/2 lb. slide hammer with T-handle. Housed in a blow-molded plastic storage case Includes four collet sizes: 3/8" to 1/2", 9/16" to 11/16", 5/8" to 1", 1" to 1-1/4". When using select the appropriate sized collet by comparing it with the application. Insert the collet, expand it to fit the hole, then attach the slide hammer assembly. It's a great set and is easy to use!