I'm loving the Ego USB battery!!! Unlike a regular PassThrough you can unplug this one and use it as a regular battery. When I got it I thought I would have it plugged in all the time I was at the computer, but turns out I only plug it in when it needs charged. I don't use it exclusively, but if I did, I figure it's good for about 8 hours of really heavy
vaping.
Another choice is the Sit N Go 510 PT that you can get from madvapes.com or litecigusa.com It's a regular 510 battery with the same USB plug in feature as the Ego USB. Little cheaper to buy, but you only get a couple hours off the cord before it will need hooked up again. Not sure how well they hold up either. I debated between it and the Ego USB and went with the Ego for several reasons. The main reason being the Janty Warranty, the second being battery life off the cord and lastly it came in stainless.
This was my alternative to getting a full kit, and I am glad I went this way. I think the battery is fantastic. You will need to order the cone separate if you want one as it does not come with the cone. I highly recommend the cone though.
Hope this helps!!! Blessings and Happy
vaping!!