The NHC855 is a shop air hose crimper that is suitable for most 1/4"-3/8" air hoses. It comes with 5 standard die sets, although there are 10 different sets available. The NHC855A is commonly used as a welding hose crimper as it can crimp 3/16"-3/8" ID hoses. The NHC860 will crimp 1/2"-1" hose (dies sold separately on this unit) and is commonly used for repairing garden hose. NHC5111A/NHC1765A are larger countertop production units for a full range of ferrules/dies. Each die set are for a fixed crimp diameter.