To activate your Yard Drinking Glass, slide the switch on the bottom of your party cup. LED Yard Glasses have a battery saving feature: when you set it down on a table, the lights will stop flashing. To activate again, just pick up your Yard Glass! Once finished for the night, flip the switch again & the LEDs will stay off. Dimensions: Height: 13.0 in. Volume: 17 oz filled to brim LED Colors: Multicolor 17oz Yard Drinking Glasses include 4 replaceable AG13 Batteries.