Drill and tap combinations produce a thread that is strong and easy to tap. 135 deg (degree) split point HSS (high speed steel) drll bits ensure fast, precise drilling. HCS (high carbon steel) plug taps are ideal for general purpose threading. Includes plastic storage case. Set includes plug taps in sizes (4-40NC, 6-32NC, 8-32NC, 10-24NC, 10-32NF, 1/4"-20NC) and drill bits in sizes (No. 43, No. 35, No. 29, No. 25, No. 21, No. 7).