This Mini Mod is designed to be smaller and more compact than a traditional pen style battery. They’re build to fit any 510 threaded cartridge up to 11mm in diameter. They work with 1g and .5g carts, top or bottom airflow. Super compact, super discreet, super powerful. Perfect for events, festivals, and traveling. Comes with a micro USB charging cord and quick disconnect lanyard. Output voltage is a constant 3.7v when fully charged, 3.2 when battery gets low. 500mah battery lasts for days! Quick charge while continuing to vape in just 30 minutes.