Nothing beats the Original! - Pet Blinkers ensure you and your pet will be seen in darkness and low visibility. Designed to be compact and inconspicuous, each Pet Blinker’s LED's emit a bright flashing light that can be seen up to a half-mile away. Made of lightweight durable plastic, Pet Blinkers are water-resistant and include a spring-loaded clasp for easy attachment. Pet Blinkers are activated by a simple on-off twist mechanism and are available in four vivid flashing colors. Using two different size clasps, Pet Blinkers will comfortably fit both small and medium breed dog collars, leads, and leashes. Pet Blinkers require 3 AG3 batteries (installed), and each includes an extra spare set. 4 LED Color Combinations – Blue: Blue/White LED, Red: Red/White/Blue LED, Clear: Red/Green/White LED, Green: Jade/Blue LED Convenient, Compact & Unobtrusive Clasp Designed For Small and Medium Breed Collars & Harnesses Water-Resistant Easy Twist On-Off Activation.