Set-3PC Megipet Dog Safety Clip on Dog Collar LED Blinker Lights Pet Blinker Flashing Collar Keychain, Batteries Included Push button on/off switch,Flash or Glow mod which has bright LED area light. Designed to keep you and your pet safe - Visible for more than 1/2 mile. Secure stainless steel carabiner -Water resistant Dimensions: approx. 1.26" x 0.75"(Diameter and thickness) Package include 3pcs dog flashing lights: 1pc blue, 1pc pink and 1pc yellow Easily replaceable batteries included,can replace the battery easily after running down of battery