Collets set Material: 45 steelIt is ER11 precision spring collet.Durable and wear-resistant, holding force, wide clamping range.Gripping Range: 1mm to 7mm.Widely used in machining centers,general milling machines, CNC milling machine, engraving machine,silver COLORhigh-speed machines, and other processing.Style: ER11Material: 45 steelSize: Show as in the picture.Gripping Range: 1mm,2mm,3mm,4mm,5mm,6mm,7mmFits metric size(s): For example,1mm Collet Fits 1mm metric ,2mm Collet Fits 2mm metric.Package Included: 7 x ER11 Collet(1-7mm)Only the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.