Hi Everyone I am just following up on my original Vivi Nova review. It was great while it lasted which was about 2 weeks I experience three problems. 1 - The Positive Center Post was too long and not adjustable so the tank could not be screwed all the way down onto the battery connection. Some people have said they have either filed down the protruding center post, others were able to use and ego-510 adapter to solve the problem 2- My first replaceable head 2.8 ohms burned out after a few days 3- The threads on the bottom that screw the tank onto the battery connector failed completely. After they failed as a test I put a pair of pliers around the threads and with light force they crushed like a tin can. Tried the same test with Stone tanks, some Attys and other cartomizers and they withstood even strong force. I have seen a few similar complaints. Hope the folks at Vision can fix they bugs because the product has potential My Stone 2 and 3 tanks are still all good. Have not had to use any replacement innards yet. My personal opinion is that the Stone 2 was the best of the lot. Only problem with that was the resistance came at 1.6 ohms despite being advertised as 2.1-2.3 ohms. I tested the replacement innards too compare and they were more accurate. I hope Vision continues to produce replacement innards for the Stone 2 and 3 tanks as promised For now, I'm sticking with the Stone 2 and 3 which I can recoil and re wick myself if necessary in the future.