The v3 is NOT a knock off, it's the colored, plastic version of the clear v2.5... that's the only difference between em. They use the same attys, metal caps and bases. I'm not sure if the plastic is a polyp/polyc mix or just polyc. I've heard cinnamon, straight banana and citrus flavors can damage the plastic tanks so I'm running my own lil experiment. (I am currently
vaping Virgin Vapor's Red Hot Cinnamon in my red tinted v3 vivi nova. I purchased a solid metal tank as well, so if they plastic one gets damaged, I have a back up. I bought these tubes, additional 2.4 ohm attys, and 2 STV novas (the metal tube with the plastic window) at Vapor Alley.
Originally, the metal base was not in stock, so I waited to complete my order. I received an email from Rick that night asking if I needed any assistance. When I wrote back about the base, he replied right away that he just got some stock in and will check the inventory. The next morning, I received an email with an attached link to the base's page on the VA site with updated inventory numbers. I placed my order, received a shipping notification the next day AND received my order a day earlier than expected. Rick's tubes are a whooping 15 cents more than other sites, but with the stellar response and delivery (it helps that he's on the east coast and closer to me than he might be to some), it is well worth it. The extra $ 3 I spent if I split the order with VA and some other supplier might not have gotten me all the items on the same day. What's the use of having a new tube and parts and no attys? Just MHO.
Happy vaping!