To activate your 14 oz. LED Skull Mug, press the button underneath. With each push, change the lights from flash, to blink, to steady, to off. Dimensions (W x H): 3.25 in. x 4.75 in.; Holds up to 14 oz. liquid filled to the brim LED Colors: 2 Red, 2 Blue, 2 Green LED Skull Mugs come ready to use with 3 replaceable AG13 Batteries.