The Vifa tweeter baffle cutout is 2.875", but you'll need two little bumps in the circle cutout for the wire connectors. You could also cutout a 3" diameter hole, but then the edge is very close to the mounting screws. You might want to order a pair of tweeters and see what I mean. The magnet is 2.75" diameter and if it weren't for the connectors, that would be all that you had to clear. If a person already has one π or two π speakers and they want to retrofit, it can be done pretty easily with a rounded file or four-in-hand.