CNC Tool Holders with High Precision & High Speed 1. Material: 20CrMnTi 2. Precision below 0.005mm 3. Rotating speed 12000rpm CNC Tool Holders with High Precision & High SpeedThe sizes of Shank: BT30, BT40, BT50; CAT30, CAT40, CAT50; JT30, JT40, JT50(DIN69871-A)The sizes of ER Nuts: ER16, ER20, ER25, ER32 & ER40