Not sure, but it was about 14" diameter - was huge. Also had it cranked to "11" most of time (old fart metalhead). I got it from stepson, just layin' around his room and thought I'd use it. I already have middle-of-the-road amp installed before.

It's doing fine so far with the sub pulled out, but I suspect it's a bad battery (pretty old) & will have the battery checked soon or if it dies again - will just keep fingers crossed for now.