This IRWIN SPEEDBOR 15-Piece Turbo TiN Proset features a Titanium Nitride Coating nitride (TiN) coating on every piece, so the fittings last longer than alternatives without coatings. This coating also reduces the amount of heat produced when the bits cut into materials. This Irwin TurboMax drill bit set features specialized tips that help you maintain your position without lateral movement, so you retain better control while you work. All these pieces have factory-measured bodies, and they produce accurately sized holes every time. The largest bits in this Irwin drill bit set have three flat edges on the shanks, so they retain a strong grip while you work.