nut for collet chuck 1.ER8,ER11,ER16,ER20,ER25, ER32, ER40 ER50 ... price and good service 3.are durable in use nut for collet chuck1.Size: ER8,ER11,ER16,ER20,ER25, ER32, ER40,ER502 ... .5M60*2.5EOC 408537M68*2.5EOC 5010043M80*2.5 nut for collet chuck