... ISO,A,AG,G,W,UN,NPT,ACME,API et Threading insert SIZE RANGES ARE 11ER/16ER/22ER11IR/16IR/22IR etc.. ... black coating,suitable for processing stainless steel(grooving insert) or universal use(threading insert). LDC shows yellow coating,suitable for processing steel ... also can produce non-standard carbide threading inserts, CNC inserts and grooving inserts.The performance of our insert can be as good as ...