53731 Klein Adjustable Hole Saw Perfect for Drywall and Ceiling Tiles   Quickly and smoothly cuts cleaner holes in drywall and ceiling tiles. Blades adjust to cut holes from 2 to 7 in diameter. Fits most 3/8 and ½...

Absolutely the best hole saw on the market.  You will make your money back the first time you use this for your speaker installations. Adjustable Ceiling Hole Saw w/Dust Trap Cuts Holes 1-1/2 inch thru 10 inch in Diameter