Only thing that bothered me, not enough to take away a star, was it is a little snug on the tank, good in some cases, I just like a bit of play because down the road if they ever do start vibrating or such, I could put a thin foam pad between them and the tank and loud pumps go quiet then. Did that with the Aqua-Tech I had prior to these because it screamed like a banshee right outta the box. Seriously impressed with these units though, and fitting snugly is probably a good thing. And by snug I mean, it fits like a glove, no forcing it on or anything, fits right down as it should, but has no play. Like it was machined to fit (On my tank anyhow).
PS - Disappointed with the FEDEX guy though, slacker entered delivery attempt when none was made since I was here the whole time, gate unlocked and open. No door tag provided, secretary and surveillance cams saw no sign of him anywhere that day, didn't even drive past. Had to pick this up 2 days later and talked to manager. Disciplinary action took place before I had even left, glad I wasn't that guy, they were really tearing a strip off him.