The bi-metal hole saw produces smooth cuts in various materials. The tooth geometry (Vario toothing) is ideal for gliding through the material and producing smooth cuts. This hole saw is made of bi-metal HSS (high speed steel), with 8% cobalt alloy, so there is less risk of tooth breakage and higher heat resistance for long lasting cutting. This hole saw is suitable for cutting wood, metal and plastic The bi-metal hole saw fits all standard adapters on the market. Diameter mm: 133, Diameter inch: 5 1/4, Working length mm: 44