uxcell ER20-1/4 CNC Workholding Engraving Spring Collet Milling Lathe Tool Product Name : Spring Collet;Model No. : ER20-1/4 Clamping Diameter : 6.35mm/1/4";Overall Size : 21 x 31.5mm/ 0.83" x 1.2"(Max.Dia*H) Material : Carbon Steel;Color : Silver Tone Net Weight : 40g Package Content : 1 x Spring Collet