6 Hss Countersink Sizes: 6.3Mm, 8.3Mm, 10.4Mm, 12.4Mm, 16.5Mm, 20.5Mm. Suitable For Milling In Various Materials, E.G. Carbon Steel, Steel Plate, Iron, Aluminum, Insulation, Pvc, Wooden Board (Soft, Hard), Plastic, Etc Automatic Center Punch: Chrome-Vanadium Alloy Pin / With Solid Spring / Handle Spherical Made Of Abs Material Against Impact Damage / Copper Main Part Against Rust / Suitable For Centering On Wood, Pvc Plastic, Iron Plate, Steel Plate, Etc. (Attention: Not Suitable For Stainless Steel And Marble!) High-Quality Material: Sharp And Durable Countersinks Made Of Hss 4241 With Titanium Coating - Guaranteed For Clean, Burr-Free Machining Drill Bits Grindable: The Bits Are Made Of Heat-Treated Carbon Steel Blades, Grindable, Sharper And Harder And Ensure Long Service Life Application: The 90 Countersink Set In 6 Pieces With 3 Cutting Edges Suitable For Machining On Metallic And Non-Metallic Materials, Such As Carbon Steel, Steel Plate, Iron, Aluminum, Insulation, Pvc, Wood Panel (Soft, Hard) , Plastic, Etc.-3