Upgrade your drilling with this tap and drill bit from Irwin Tools. This Irwin 80235 is a 5/16-inch to 18 NC tap and a letter G drill bit set. The high speed steel drill bit is guaranteed to offer accurate and fast drilling. On the other hand, the high carbon steel plug tap is perfect for any types of threading. Since 1885, innovation has been the trademark of Irwin Tools. They are dedicated to giving high-quality tools for users and skilled tradesmen. Here at PlumbersStock, do our best to provide quality products like this at competitive prices. We pride ourselves in striving for excellence in every aspect of what we do.