Welcome to a whole new world of nighttime visibility. Two ultra-bright LEDs send light through an integrated optical fiber to create full-length illumination so bright you need to see it to believe it. Featuring the convenience of rechargeability and easy push-button operation, the Nite Ize NiteDog Rechargeable LED Collar - XL lights up for more than six hours on a single charge. Its optical fiber technology transmits light throughout the entire length of the collar without loss of light output and offers both constant glow and flash mode. The high-quality metal belt-buckle style closure is simple to adjust. This highly water-resistant collar is designed for ultimate durability.