Pramet Threading Insert, Full Profile Negative, TN Insert, 16 Insert, Triangular Shape, External Thread, UN Thread Standard, 18 Threads per Inch, 3/8 in Inscribed Circle, 0.137 in Thickness, 0.65 in Length, ISO Code: TN 16EL180UN T8030, Manufacturers Grade: T8030, Left Hand Cutting Direction, Carbide, Material Grade: H, K, M, N, P, S