Black oxide high-speed steel dill bits are ideal for production, maintenance or portable drilling jobs and are surface treated with abrasion-resistant black oxide. Set contains one High Speed Steel Hand Plug Tap and the matching size. Black Oxide High Speed Steel Drill Bit Hand taps are the most versatile taps for hand use, or for tapping under power. Hand taps are also appropriate for tapping the vast majority of materials in through or blind holed conditions.