For those of you who are reading the previous reviews and wondering “how huge is this thing?”… It’s big. The measurements for the cap are roughly 11 inches tall and 4 inches round. I have attached a pic of it next to a typical 16 oz can and you can see that it is double the size if not bigger. The cap itself installed easily and was easy to charge. I used a head light bulb instead of the supplied resistor since you can tell using the bulb when the cap is charged up. It keeps my 800 watt amp with 3 10 inch MTX thunder 5500’s running great with no headlight dimming, or degradation of bass.