This seven-piece set is ideal if you want to prepare electrical installations and drill holes in softwood and semi-hardwood, insulating boards, drywall, plastic or metal. It contains six hole saw blades made from bi-metal with 40, 54, 65, 68, 74 and 86 mm, a mandrel with 5/8″ thread and a centring drill bit ( 6 mm) made from high speed steel. It lets you drill exact holes with a cutting depth of 55 mm. The specially alloyed tool body with HSS toothing ensures a long service life and running smoothness. The hexagon shank ( 11 mm) makes the hole saw blades quick to secure in the chuck of your power drill or cordless screwdriver. The set comes in a high-quality two-component plastic case for transporting the parts safely and storing them neatly. The hole saw blades are TV-tested, meaning you can be sure of safe, quality products.