I've had an air pump for years that plugged into the car charger. It finally died mid pump. I got this one to replace it. I've used it a couple times now. It is soooo awesome to set your tire pressure and have it stop at that point automatically! With my old one I had to stop, unhook, check pressure, hook it up, again...you get the picture. Holds it's charge pretty well, but if you needed it and it wasn't charged you can hook it to car or electrical outlet.