YMW Zelx SS 7/8-9 Spiral Point SS Plug Tap, Thread Limit H4, Number of Flutes 3, Chamfered Plug Lead 3 to 5, Finish/Coating Black Oxide, Material: Vanadium High Speed Steel, Length of Thread 1.339, Overall Length (Inch) 4-11/16, 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