Pramet WNMG Insert. WNMG Negative Turning Insert for use with DWLN and PWLN Holders and Bars. Excellent for machining Steel Acceptable for Cast Iron and Hardened Steels. T9315. Excellent for machining Steel and Stainless Steel Acceptable for Cast Iron. T9325. Excellent for machining Steel Acceptable for Stainless Steel. T9335