Description: These spring collets are made of high quality 65Mn spring steel for CNC milling lathe tool and work-holding engraving machine. There are total 6 collets of various sizes in on set which can basic meet your need. Each collet is well packed in separate protective container with label so you can easily distinguish them. Collet must be placed into collet chuck nut before inserting into collet chuck. Specifications: Material: 65Mn spring steel Model: ER32 Range: 10mm, 12mm, 14mm, 16mm, 18mm, 20mm Height: 40mm / 1.57" OD: 31mm / 1.22" Run-Out Tolerance: <0.008mm Weight: 753g(approx.) Package Includes: 1 Set(6pcs) x Collets Note: 1. Please allow 1-2mm error due to manual measurement. Thanks for your understanding. 2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.