Ruffwear - Beacon Safety Light for Dog Gear HIGH-INTENSITY LED SAFETY LIGHT: The Beacon High-Intensity LED dog light provides a hemisphere of light to enable you to have a clear view in low-light conditions. THREE LIGHT MODES: The Beacon allows you to track your dog with one of three light tracking modes: slow flash, fast flash, or always on. TWO ATTACHMENT OPTIONS: The Beacon can be attached to your dog's gear by means of the integrated clip or the Quick Ring. EASY BATTERY REPLACEMENT: No tools needed when it comes time to replace the battery. Simply twist the back off and insert batteries. Each Beacon light comes with two CR2032 coin cell batteries to get you started. COMPATIBILITY: The Beacon is compatible with all Ruffwear wearable gear. The Beacon attaches easily to collars, packs, harnesses, apparel, and life jackets, and can also be attached to runners, hikers, cyclists, kids, and equipment for added safety.