The small-sized light measures just 1.73" x 0.97" x 0.62", perfect for smaller dogs. The PetLit LED collar light features a green-colored paw print design on light. To operate simply twist the body of the light. This collar light puts out a continuously illuminated bright white light that is easy to see, even from far away. The battery-powered accessory runs on 2 CR927 lithium coin cells, which are included with purchase. Batteries included.