Brand: RUKO Item: Machine tap Material: 5% cobalt high-speed steel (HSSE-Co5) Application: Thread making Finish: Bright Thread Length: 0.79in Overall Length: 3.6in (91mm) For Use On: Stainless steel, brass, steel, aluminum, bronze, plastic and cast iron Thread: 5/16-18 UNC per ANSI/ASME B1.1 Tap Drill Size: Letter size F Shank: Square shank per DIN 10, reinforced for through threads RUKO machine tap, 5/16-18 UNC, square shank per DIN 10, reinforced for through threads, 5% cobalt high-speed steel (HSSE-Co5), bright finish.