The DazzVape U-Key is a stylish battery that's extremely portable and easy to use. It can be filled up with 0.5ml or 1ml and features a 10 second preheating function. It uses a single button to operate and is a variable voltage device with the following sections: 2.8V, 3.2V, 3.6V, 4.0V. It also has a smart memory function, a built-in 350mAh battery, and safety features include short-circuit protection, open-circuit protection, and over-charge protection. Overall dimensions measure 68mm by 35mm by 21mm.