I have a dimarzio will power middle P bass pickup. Very aggressive P bass pickup. When bolted down it's possible to see indentations where the pickup magnet is below the covers but there's no cracks in the covers themseves. It's just somthing that happens with this style of cover. when you screw them down it puts stress on the covers and eventually you can start to see the outline of the pickup under the covers. It's kind of hard to explain but the less you screw it down (thinner stuffing under the pickup maybe) the less you can see the indentations. Anyway I just wanted to try to describe that so there's no suprises. The sound awesome and there's tons of wire left to reach any pot on any bass I'm sure. 50 bucks shipped anywhere in the lower 48.