Switch out end mills the easy way-just attach the quick-change collet chuck to your mill and slip your end mill into appropriate collet. Sets includes a collet chuck, 1/8", 3/16", 1/4", 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4", 13/16", 7/8", 15/16" and 1 collets, spanner wrench and moulded plastic case.