Carbide, like this 10 piece set with 5 hole saws in the body. They are very heavy and designed for the SDS MAX hammer drill or SDS PLUS. Drill bits for drilling masonry, concrete, cinder block and softer rock. This set includes 12" shanks for SDS MAX and SDS PLUS impact drills. which uses an 18mm shank. I have both; They will not work with a normal impact drill (without SDS Plus/Max). TCT hole saws fit any supplied shank. These hole saws must be used in a hammer drill that accepts the Slotted Drive System (SDS) tool bits and has a "hammer" rotation setting. The impact drill delivers impacts in the direction of rotation; The hammer drill delivers an impact parallel to the chisel with or without rotation. A spinning kick is used for this. They do not require water to use, although this will help prolong the life of the hole saw. This set is impressively strong, with thick TCT 3-edged teeth and heavy gauge steel hole saws that have a scrap pocket on the side. I really appreciate having the 12" SDS Plus and SDS MAX shafts. There's even a small wrench for tightening the 8mm pilot drill (2 included, also with TCT tip). Great set of 5 hole saws size: 1-3/. 16" (30mm), 1-19/32" (40mm), 2-9/16" (65mm), 3-5/32" (80mm), 3-15/16" (100mm) I recommend this REETAI -FOUR Store 10pcs SDS Plus Concrete Hole Saw Sets Carbide Wall Hole Drill Bit Sets for Cement Stone with Concrete Cement Connecting Rod for Masonry Great set for drilling holes I hope you found the information and my review helpful.