The Puplight is one of my favorite products.  In fact, when selecting products to add to our website, this was one of the first I chose. 

If you walk your dog while it is dark, you will love this product.  The Puplight is an LED light attached to a comfortable elastic collar.  It illuminates up to 200 feet ahead, allowing drivers to easily see your furry friend.  Three AAA batteries last at least 150 hours and its unique design keeps the light out of your dog's eyes.

The elastic band fits neck sizes from 8" to 26" and can either be buckled on or slipped over the head.  It can be worn along with your dog's own collar or the light can be attached to the existing collar.  It only weighs 2 1/2 ounces, making it comfortable for the smallest dogs.

Keep your dog visibal at night - to both you and traffic - by using Puplight.  You can find more information here.