Designed with the ball-obsessed pup in mind, this durable rubber ball features bright Red LEDs. It is motion activated and also has an auto shut-off function after ten minutes giving you time to find it if your dog has gotten distracted, and to optimize the replaceable, long-lasting batteries. Diameter is the same size as a tennis ball and invincible to water or slobber, this tough little ball is ideal for playing fetch with the ball-loving dog who wants to take it for a swim or play fetch for hours into the night. This ball is not intended as a chew toy, nor is it intended for pets under 12 months old. It is meant for supervised use only and for enjoying playing fetch with your dog. Please tighten the battery cap securely in place using a flathead screwdriver and check the tightness regularly. Nite Ize SpotLit LED is a great mini-beacon whenever you need a little help in the dark. Set in a lightweight stainless steel carabiner, it attaches quickly and securely to key rings, jackets - just about anything with a hook or zipper. Its long-lasting LED provides an ambient glow bright enough for everything from reading fine print to finding your car door keyhole. Attached to things like tent lines and camping gear, it provides instant location of hazards and necessities; attached to your person (jacket, backpack, running belt) it tells other people where you are, when they might not otherwise see you.