Fits with most 510 Cartridges (maximum – 11.5mm) USB-C Cable Included 510 Battery fits up to 2g Carts | Three rapid draws on device to adjust voltage. Two rapid draws for pre-heating (Green: 3.0V / Red: 3.8V / Rainbow: Preheat) Thermal Color Changing Changing Version Red to Yellow Royal Blue to Purple Green to Lemon yellow Fits with most 510 Cartridges (maximum – 11.5mm) USB-C Cable Included 510 Battery fits upto 2grams Carts Instruction: Three rapid draws on device to adjust voltage. Two rapid draws for pre-heating Voltages: Green – 3.0V Red – 3.8V Rainbow – Preheat