1pcs Straight Flute Taps:Thread size: 4-40 UNC (right hand); blade length: 17mm / 0.67"; square shank side width: 2.3mm / 0.09"; shank dia: 3mm / 0.12"; total length: 50.5mm / 1.99"1pcs Twist Drill Bits:Drill size: 2.3mm (right hand); cutting edge length: 21.5mm / 0.85"; shank dia.: 2.3mm / 0.09"; total length: 52mm / 2.05"Descriptions:Thread tap adopts straight flute design, with clear threads and no burrs. Screw threading tap provides downward chip removal, fast and precise tapping, suitable for through holes or shallow blind holes.Twist drill bit adopts a spiral flute chip space design to remove chips quickly and cleanly. Cutting edges provide neat and smooth cuts. Use an appropriate lubricant (such as cutting fluid or oil) to reduce friction and heat build-up.