The Yocan UNI is an ergonomic and discreet VV Box MOD, which is perfect for oil vaping. Working with built-in 650mAh battery and adjustable three levels voltage indicator light, the Yocan UNI MOD can bring you stable vaping experience. And the UNI adapts any types of oil cartridge. To provide you with an incredible vaping experience, the Yocan UNI has a built-in preheat function that warms up your oils before the first use. So the Yocan UNI is really perfect for oil vaping.