The Energizer USB 4' Leash is made with wide fiber optics for maximum light transmission. The LED lighting features solid, slow and fast flash modes. This leash coordinates with the Energizer collars (sold separately) and features USB rechargeable battery, metal hardware, designer mesh, reflective stitching and a rubber paw on/off button. With universal USB charging and Energizer approved electronics (a trusted leader in battery technology) the Energizer Leash will provide long distance visibility for your dog.