YMW Zelx SS 4-40 Spiral Point SS Plug Tap, Thread Limit H3, Number of Flutes 2, Chamfered Plug Lead 3 to 5, Finish/Coating Black Oxide, Material: Vanadium High Speed Steel, Length of Thread .335, Overall Length (Inch) 1-7/8, Thread Standard UNC, Tapping Materials: Stainless Steel, Alloy Steels and Ductile Iron Tapping Stainless Steel: 12-70 SFM, Tapping Alloy Steels: 10-45 SFM, Tapping Ductile Iron: 15-60 SFM