Round-2 1/2" - Our first and most popular product over the past 24 years! Flashing buttons are the easiest way to attract attention to your cause. Pinning the button activates a bright LED light that continuously flashes for over 100 consecutive hours. Simply unpin to turn off. May be worn on shirts, back packs, and other apparel. This simple yet effective method is an ideal way to shine some light on your logo or message! Replaceable batteries included.