29 Pcs ER40 Precision Spring Collet Set For Milling Lathe CNC Chuck Bit Holder. 29 PCS PRECISION ER40 COLLETS including: 1/8", 5/32", 3/16", 7/32", 1/4", 9/32", 5/16", 11/32", 3/8", 13/32", 7/16", 15/32", 1/2", 17/32", 9/16", 19/32", 5/8", 21/32", 11/16", 23/32", 3/4", 25/32", 13/16", 27/32", 7/8", 29/32", 15/16", 31/32", 1.