This screw tap drill bit set is made of high speed steel, long lasting and good abrasion resistance. Compact and portable, this tool set is perfect for tapping, suitable for soft metal. Features: High speed steel screw tap bits are long lasting and good abrasion resistance. Standard thread distance design, clear and tidy, no burr. With these machine thread taps, you will have a smooth tapping experience with them. Specifications are marked on the surface, convenient to choose. Suitable for soft metal and materials with low hardness such as aluminum sheet and iron plate. Specification: Material: High Speed Steel Color: Silver Standard: Metric Shaped Optional Package List Edge Diameter Pitch Edge Length Total Length Outer Diameter Point Head 1 x ST2.0*0.4 1 x ST2.5*0.45 1 x ST3*0.5 1 x ST4*0.7 1 x ST5*0.8 1 x ST6*1.0 2mm 2.5mm 3mm 4mm 5mm 6mm 0.4mm 0.45mm 0.5mm 0.7mm 0.8mm 1.0mm 13mm 16mm 18mm 22mm 25mm 24mm 50mm 50mm 56.5mm 61.2mm 70.5mm 71.5mm 2.6m 3.3mm 3.9mm 5.2mm 6.4mm 7.7mm Flat Head with Middle Hole 1 x ST8*1.25 8mm 1.25mm 24mm 81mm 9.9mm 1 x ST10*1.5 10mm 1.5mm 30mm 89.5mm 12.3mm 1 x ST12*1.75 12mm 1.75mm 31.5mm 94.5mm 14.6mm 1 x ST16*2.0 16mm 2.0mm 33.5mm 103.5mm 19.2mm 1 x ST18*2.5 18mm 2.5mm 35.5mm 98mm 21.8mm Note: Please allow small size error due to manual measurement. Thanks for your understanding.