The Black Diamond Iota is charged with a micro USB cable. It takes an hour or so to go from no charge to a full charge. It has a small light that turns green when charging is complete. Rechargeable headlamps are very convenient, since they can be charged on-the-go from power banks already used to charge phones and GPS watches. A micro-usb port is located on the side of the Black Diamond Iota. There is a plastic flap to protect the port from rain. 40 hours at completely dim or about 2 hours at completely bright Specs: * Lumens:  150 * Weight:  1.9 oz (56 g) * Lithium ion, micro USB rechargeable battery (takes 1-2 hours to charge) * Battery Life:  Low beam ~40 hours / High beam 2 hours * Max Distance:  High beam 131 feet (40 m) / Low beam 23 feet (7 m) * Water resistant (IPX rating: IPX4, Storm proof—Tested to withstand rain and sleet from any angle) * Settings include full strength, dimming and strobe * PowerTap Technology allows fast and simple transitioning between full and dimmed power in order to instantly increase illumination in distance or proximity modes * Three-level power meter shows remaining battery life for three seconds after switching on headlamp * Lockout feature safe guards against accidental use when stored in a pack or pocket Pros: * Lightweight * USB rechargable * Small * Strong beam * Dimmable * Reasonable battery life * Recharges quickly