Material: Made of high resolution steel, high hardness, anti-rust, sturdy and durable. Size: 16mm, 18mm, 20mm, 22mm, 25mm, 26mm, 28mm, 30mm, 35mm, 40mm, 45mm, 50mm, 53mm, to meet your different needs. High precision drill bits, highly resistant to impact and wear, providing smooth cutting. Sharp and anti-cut teeth with low consumption, for a long-lasting product. Multiple uses: Suitable for steel plate, iron plate, stainless steel and all kinds of thick materials. The perforation, the maximum depth is less than 5 mm. High-speed steel teeth for fast cutting of clean and round holes. Suitable for hand electric drill, motorized drilling machine on column and magnetic drilling machine with separate cable. 13pcs Hole Saw Drill Bit Set HSS Carbide Tip Stainless Steel High Speed Steel 16-53mm for Plastic Steel Metal Wood. High speed steel and stainless steel hole saw drill bits, sheet metal reamer. These drill bits have undergone special heat treatment, are sharp and have very high strength.