The 7 piece set includes the quick change tool post, and the 4 most common holders to tackle even the most demanding jobs. Our #1 and #2 holders also give you the capacity to hold 3/4" tools over the industry standard 5/8" along with a standard #1 holder as well. Also included #4 boring bar holder with 1" capacity and a reducer bushing to 3/4" if needed. Also included is a #7 grooving and part off holder with a 11/16" capacity. Finally is a #10 knurling holder which uses special high quality GCr15 knurling wheels. They use a Zinc Nitride (ZiN) coating on all of their quick change hardware to give it a more durable and rust resistant finish while allowing for smoother thread action.