The IRWIN HANSON 1/4′ – 28 NF Tap and No. 3 Drill Bit isideal for creating precise holes and 28 clean threads per inch in metal forgeneral purpose drilling. The drill bit is constructed of high speed steel forfast drilling, while the tap is crafted of high carbon steel for durability.From the Manufacturer Drill and Tap Packs, include 1/4-inch – 28 Tap + No. 3Drill. Black oxide finish on all high carbon steel Hanson taps with semi-porous matte surface that causes cutting oil to cling, carrying the oil intothe cut more effectively, thus reducing the drive torque required and loweringcutting temperatures. Oxide surface-coating also reduces tendency for chips toweld to the Tap, resulting in lower cutting temperatures and freer chip flowto increase tool life. Irwin tools are made of only the finest materials,manufactured to exacting tolerances.