The YFTK Across Vape Roulette Style RTA is constructed from 316 Stainless Steel in 22mm Diameter. The RTA supports MTL vaping and DL vaping, which comes with a huge E-juice capacity tank tube with top refilling and juice control by rotation of the drip tip base. What's more, the RTA also comes with two air roulettes. one for MTL and the other for DL. It is to change the air hole settings via rotating the air Roulette.