carbide internal & external threading insert SIZE :11ER/16ER/22ER 11IR/16IR/ ... ,G,W,UN,NPT,ACME,API carbide internal & external threading insert SIZE RANGES ARE 11ER/16ER/22ER11IR/16IR/22IR ... 16 W LDCAll our threading inserts are with PVD coating,all our turning tool inserts are with CVD ... interested in our products.WENLING LIFENG PRECISION TOOL CO.,LTD!!! carbide internal & external threading insert