* For cutting all types of internal threads* Tough, carbon alloy tool steel for long life* Drill size permanently marked on each tap* 20066: 3/16-24 NS* 20067: 3/16-32 NS* 20068: 1/4-20 NC* 20069: 1/4-28 NF* 20070: 5/16-18 NC* 20071: 5/16-24 NF* 20072: 3/8-16 NC* 20073: 3/8-24 NF* 20074: 7/16-14 NC* 20075: 7/16-20 NF* 20076: 1/2-13 NC* 20...