StaircaseWit, I just received an 18650 tube from Gotvapes. The tube does not fit flush if your using their 18500 battery with a nipple. They fail to tell you this on their website. I emailed them and asked if a 18500 flattop would work to make it a flush fit, their response was that the unit will have a gap with the 18500 and a bigger gap when used with a kick. I replied that the gap annoyed me and could i return the tube and battery for an in house credit. They replied, NO, as the part was not defective. This is when i went off on them stating that, to me, the part is defective if it does not fit correctly! They closed the ticket on me (granted I added a few not so nice words) I've spent $300 with Gotvapes over the past three months yet they will not let me return a $10 item for an in-store credit. Pretty crappy way to do business if you ask me. Taking my business elsewhere. That being said, If you want this 18500 tube I'll give it to you, just send me a PM with info. As for the batteries, which they also would not let me return, I'll just use them in my Provari and give my 18650's a little time off. Gotvapes can take their aloof attitudes and stuff em'!