The Nite Ize GlowStreak is a light-up fetch ball for playing with your dog after dark. The tough rubber ball, about 64 mm (2.5") across and the size of a tennis ball, has a protected inner LED module that lights up in colour-changing Disc-O mode. It is motion activated, so a bounce switches it on, and it turns itself off after 10 minutes without movement. The ball is waterproof and floats, so it is fine for dogs that like to swim, and the grooved surface is easy for small and large dogs to pick up. It runs for about 35 hours on two replaceable CR2032 batteries, which are included, and weighs about 110 g.