Each sets come with 1-Drill America Carbon Steel NPT Tap and matching Drill America High Speed Steel Black Oxide Drill Bit. Drill Bit Information: A dependable, general purpose drill designed to perform in a broad range of materials in the iron and steel families. Ideal for production, maintenance or portable drilling jobs. Surface treated with abrasion-resistant black oxide. Tap Information: National Pipe Taper Taps are appropriate for threading a wide variety of materials both ferrous and non-ferrous. The nominal size of a Pipe Tap is that of the pipe fitting to be tapped, not the actual size of the tap. The thread tapers 3/4 of an in per foot. All Pipe Taps furnished with a 2-1/2 in. to 3-1/2 in. thread chamfer. NPT threads require the use of a sealer like Teflon tape or pipe compound. Carbon Steel Pipe taps are designed to clean and/or re-thread damaged or jammed pipe threads.