HIGH VISIBILITY yellow strap with four LED's for additional safety, powered by a replaceable CR1023 battery that has a battery life of up to 1,000 hours when on flash mode. IDEAL REFLECTIVE led armband for running, walking, cycling and all outdoor activities SIMPLE ADJUSTMENT made using the velcro strap allows the armband to fit all sizes and to fasten to either arms, legs, rucksack, bum bags, saddle stems etc-soft terylene backing for comfort when worn directly next to the skin.