1.ER8,ER11,ER16,ER20,ER25, ER32, ER40 ER50 2.We supply competitive price and good service 3.The products are durable in use nut for collet chuck1.Size: ER8,ER11,ER16,ER20,ER25, ER32, ER40,ER50 2.Type: UM, T1,T2, A, B, MINI. 3.Material: alloy steel 40Cr 4.Hardness: HRC42-45