With a nice loud whistle you're sure to be heard but listen, my friend, may I have a word? If you want someone's attention, you don't have to be tense With this flashing green whistle, you'll engage more than one sense!! To activate simply twist the battery pack on the top of the Green Flashing Whistle. The lit whistle will flash green leds, this is the only light function. Each green whistle comes with a green lanyard. Dimensions: Length: 2.78 in. Width: .62 in. Lanyard: 36 in. LED Colors: Green Green Flashing Whistles include 3 replaceable AG13 Batteries.