This scientific PHD Vaporizer Battery fits most thick oil cartridges up to 11mm diameter. A magnetic cart connector with universal 510 threading allows for cartridges to be dropped into the battery's cart chamber, making it simple to switch them out. This unique vape battery also functions as a pre-heat device by pre-warming the entire cartridge for optimal vaping performance. Dual Pre-heat Operation: Cartridge Pre-heat Mode - Heats from the coil up. During the first 1-15 seconds, the cartridge preheats at 1.5v represented with a pulsing BLUE LED. Shell Pre-heat Mode - Heats the entire cartridge simultaneously. During the remaining 15-45 seconds, the shell of the battery preheats at 1.2v represented with a pulsing GREEN LED. Features & Specs 0.62 x 3.86 inch (16mm by 98.1mm) dimensions 650mAh battery 4 voltage settings (2.8v - 4.0v) Metal body Side button activated Magnetic cartridge drop-in feature 510 threaded connection Dual pre-heat option (Cartridge and Shell pre-heat modes) Over Vape protection (12 seconds) Multiple color options available 6 month limited warranty Includes: USB charging cable and 510 magnetic connector