Bits for Hardened Metal, Stainless Steel, Cast Iron, Plastic and Wood with Indexed Storage Case, 1/ 16"-3 /8" tried them recently and they work great, you will never have many exercises. They are made of carbon, making them ideal for piercing hard metals and other materials. It is excellent for drilling plastic, wood, steel, aluminum and many other things. In total you get 15 drills plus a case. You get 2-1/16, 2-5/64, 2-3/32, 7/64, 1/8, 9/64, 5/32, 11/64, 3/16, 1/4, 5/ 16 and 3/8s. I love the fact that you get double the smallest three drill bits because those sizes break first no matter how careful and accurate you are. This also comes with a hard case, the case is well made with a nice latch that slides up and down to keep it closed. Each drill has a safe place to drill and each place is marked with the size of the drill for you to organize. (See photos) Overall this is a great carbide drill bit set and you get a nice carrying case. I would recommend them