Need the name of a drill bit

I’ve been putting off modding my T5 for a while now, but I’m now determined to get this thing done before November. One thing I need to do is move the start and select to the back of the case, but I don’t know the name of the bit needed to drill a 24mm hole. I’ve seen them, I know what the damn things look like, but I can’t think of what its called so I can order one. The one I saw, and I’m not sure if this describes all of them, was like an umbrella, with a drill bit in the center and a round cutting blade around it, like an upside down pie tin. Hope this isn’t too dumb a question, its just that its so common in discussions around here no one names it.

Edit-Never mind, I found it finally, its just called a hole saw. Can’t delete this thread, so I’ll just mention its closed.

Hole saw.

Thanks, just beat my edit, I found a DeWalt bit that works just fine for me. Thanks though.