Review on Drilax Diamond Concrete Masonry Inches Cutting Tools ~ Industrial Drill Bits by Eugene Cox

Had to drill a 3.5" hole in a concrete block wall. I used this core drill in my 18 volt drill and it took about 5 minutes to drill the hole on each side. The beat still looks good. Would recommend this bit if you only need to drill a few holes and don't want to pay a high price per bit.