They haven't been in stock yet,,,,,think they were saying 20sep?? it was going on sale. I love it,,,on the SD as some other people will tell ya fully charged It's sposed to be round 4.2 V. Though as the batt dies the volts drop off also. From what I've noticed is that you can can keep that fully charged vape going quite alot longer on the battery. I think it was Darth saying that he had gotten a earlier version of the booster + it did not work on his SD. So it's just 1 of those things you know.