To activate your 20 oz. LED Skull Mug, press the button underneath. With each push, change the lights from flash, to blink, to steady, to off. Dimensions: H = 5.5 in.; W = 5.5 in. (includes handle) Volume: 20 oz. LED colors: Red, Blue & Green LED Skull Mugs come ready to use with 3 replaceable AG13 Batteries.