Never used - NWOT Unisex size Small/Medium (see photos for size chart) I don’t know the specific measurements of my head, but I’d say it’s average to ever so slightly small, and this beanie is a little too big for me. Battery included (cable to connect to beanie is attached to beanie). Cable to charge battery (micro USB-A) not included ***Website: The ActionHeat 5V Battery Heated Winter Hat is designed for people who take on the outdoors, head-on. Featuring a tight, stretchy fit to trap your head's natural heat, you will love the extra comfort of strategically placed heating panels on both ears. Once the beanie is powered on, the heating elements quickly heat up your ears and head in under 10 seconds. The rechargeable 5V lithium-polymer batteries deliver 3 levels of heat, controlled by the temperature controller on the hat. The hat can reach a maximum temperature of 130F while lasting up to 4.5 hours. HOW TO USE: Charge Up – Fully charge power banks with provided charger kit. Plug-In – Connect the power bank to USB plug located in the pocket on the back of the head Turn On – Press and hold touch-button control on the hat for 3 seconds. Press touch-button to adjust the temperature. Features: Machine Washable - Gentle Cycle Built-in heating panels strategically placed over both ears Touch-button control technology (3 settings) 4 LED power indicators display power banks battery life Battery Voltage: 5-Volt