Do not listen to the reviews below. These core bits are top quality bits. Anyone buying a bit of this type should due their homework. This bit is part of a core drilling system. You will also need the "arbor" that will fit your drill. Typically a SDS max for Hilti drills. Then you will also need another bit to use as the arbor. I have a full set of these from 2in thru 6in and I have put them thru hell. Concrete to brick, through rebar and right thru wood. You wont find a better bit in this price range. They work so good that my 2in was stolen on my last job and now I have to buy another one. If you dont want to invest in a nice set like this then go with the one piece option that they sell but your better off with the set. (For the record I am not a jersey girl. I'm in my wifes account. But even she knows how much time and money these bits save our company)I have several different sizes of these dewalt core drills now. I add them as I have a job that calls for one, and amazon always has the best price. they always do the job and never let me down .The only trouble I have is that they are near impossible in the field to remove from the shank. I typically take them back to our shop and disassemble with a couple wrenches and a vise.I need to drill five inch round holes in solid cement. For a dry drill, this works quite well. It should be stated somewhere that this bit does require both the shank and centering bit, also, so there's an extra $75 or so. Also, this bit cannot do well in aggregate. Smooth cement and concrete it does quite nicely in, though. When you get to the maximum depth (about 3 inches) then pull the bit out and chisel out the initial cut, then you can finish drilling. I've gotten 20 holes out of it without resharpening yet.These core bodies last quite some time. Yes, they will dull out with repeated use, but that is to be expected. Other than dulling, these bits cut a clean hole in a short while. Docking one star due to the fact that it needs to be used with the spline shaft and centering bit. Neither of which are worth their weight.I own a metal fabricating company. I use this core bit to install pipe railings. It drills holes like butter.Works as it should.Works as it should.the add does not show the optional spline or sds drive shankes needed for this tool the're expensive! now i have to weld a broken spline shank i saved ,not everyone can do this.i,m not happy i suggest you change the add