Tooling kits include hardened steel toolholders and high speed steel inserts for turning, threading, profiling, and cut-off work. Inserts are T-15 High Speed Steel (HSS) hardened to Rc 65-67, then finish ground on all sides. They deliver excellent slow speed performance, precision interrupted cuts, and a smooth finish on stainless steel, Inconel, Monel, exotic metals, and plastics. Square shank toolholders and boring bars are CNC machined from 4140/4142 steel bar stock, hardened to Rc 48-50, and then black oxide coated to resist corrosion. Includes one " square bar, 5" long with offset end pocket for cutting ID and OD threads; plus, two high-speed steel inserts, TNMC-32NV and TPMC-32NV. Mfg: Brownells SPECS: Bar - .500" shank, 5.0" OAL, with end pocket offset for ID and OD threads, 1.375" minimum bore diameter, 60°. Inserts - .375 IC, .125 thick, .150 hole. T-15 HSS, one TNMC-32NV and one TPMC-32NV. Includes two 6-32 FH screws and 5⁄64" hex wrench.