T 5 dog devices with collar are top-mounted, high-sensitivity GPS/GLONASS receivers that use LED beacon lights activated from Astro® 320 and Alpha® 100. The lights work in low-light conditions and at night, and are visible up to 100 yards away. Rugged and water-resistant to 10 meters, these tracking-only dog devices are tough enough to run wherever your dog runs, up to 9 miles away. T 5 ships with a 1-inch blue collar strap. Replacement straps are available in multiple colors.