This is #NI-NND0310M Nite Dawg L.E.D. Dog Collar - Medium Red. The Bright RED L.E.D. either flashes or glows to give away your dog's whereabouts constantly as it is visible up to 1000 feet in the dark. It is made of flexible, light-up polymer core surrounded by strong nylon webbing, not to mention it's weather resistant! The 100,000 hour L.E.D. life ensures that you're getting enough bang for your buck, plus it comes with another long life replaceable battery! The collar is a Medium and measures 13" - 18".