Collets and Sleeves HC Hydraulic Chuck Sleeves Catalog Numbering System How Do Catalog Numbers Work? Each character in our catalog number signifies a specific trait of that product. Use the following key columns and corresponding images to easily identify which attributes apply. 20MHC160M 20 M HC 160 M System Size System Value Sleeve Style Sleeve Bore Size Identification Value 12 = 12mm M = Previous two HC = Hydraulic Chuck metric (xx.x) M= 20 = 20mm numbers builtin metric 010 = 1mm Sleeve bore size builtto metric values 32 = 32mm values 160 = 16mm (blank) = 50 = 1/2" 250 = 25mm Sleeve bore size built to metric values 75 = 3/4" inch (x.xxx) 12 = 1-1/4" 0125 = 1/8" 0500 = 1/2" 1000 = 1" WWW.WIDIA.COM I3