I bought this one and love it! You have to get a USB adapter that will give you enough
juice for it to be 5 volt. I have three adapters sitting next to my bed one for an
ecig, one for my phone, and one for my iPad. The one I got for my iPad is the only one I own that gives enough
juice. I can go from one to the other and it's like night and day, but using it at 5 volts is wonderful. Plus it's ONLY $12.95! I love iVape, he has some wonderful prices.
510 USB Passthrough (Manual, Black)
Good luck, hope you find one that you like.