12-13mm Clamp Dia ER20 Stainless Steel Spring Collet CNC Milling Lathe Product Name : Spring Collet Chuck;Model No. : ER20-13 Clamping Range : 12-13mm/0.47"-0.51";Clamping Diameter : 13mm/0.51" Overall Size : 20 x 31mm/0.79" x 1.2"(Dia*Length);Material : Stainless Steel Color : Silver Gray;Net Weight : 25g Package Content : 1 x Spring Collet Chuck