The sporty pulsating Electro-Luminescent glow of the Visiglo collars make these perfect for drawing attention to your pet at night. Visiglo illuminated collars feature top quality components. The electronics have been engineered to maximize battery life and wire brightness. Visiglo collars utilize a garment-suitable nylon with an extremely high thread count, resulting in durable collars that are more comfortable for dogs to wear. These collars utilize a low profile power pack using high-capacity CR2025 batteries (included and replaceable). Small collars adjust from 10"-14", Medium collars adjust from 13"-20", and large collars adjust from 16"-26". Available in your choice of blue or green EL Wire.