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. Pet Blinkers will comfortably fit large dog collars, leads, and leashes. Pet Blinkers require 3 AG3 batteries (installed), and each includes an extra spare set. Be Seen – Be Safe – Get your Pet Blinkers today! 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 Large Breed Collars & Harnesses Water-Resistant Easy Twist On-Off Activation.