I found the original w a n t s p l a y e r p r o g r e s s t ocarryovertodestinysequel , it is from 2014 . Things could have changed by now <| sep |> batteryb is the one that I used you can check the details there . About 5 . 5 in x 5 in x 1 . 8 in for dimensions , and they advertise it will power a 2 channel system for 20 hours which from my experience is pretty accurate . You can double that to 40 hours if you get the second expansion battery and they can both fit underneath the driver ' s seat of the car . There ' s a sweet spot they fit where they wont interfere with sliding the seat and are far enough forward you can still have a passenger in the back seat . Charges while your car is on through an ACC circuit . <| sep |> I ' m at day 206 for 2 suppressors myself . I called the ATF this week and it ' s still pending . I was hoping maybe approved and just waiting for the mail .