The SirEEL 380mAh Preheat Variable Voltage Battery is a premium, slim pen‑style vape battery designed for compatibility, versatility, and long‑lasting performance. 380 mAh high‑capacity lithium‑ion battery for extended use between charges. Three adjustable settings — typically 2.7 V, 3.1 V, and 3.6 V — to match different cartridge oils and user preferences. Built‑in 10–15 second preheat mode (usually 2 button clicks) to warm oil for smoother, more consistent draws. Standard 510 threading for universal fit with most cartridges and atomizers.