High Visibility LED Armband: Made of highly reflective material, the LED reflective armband has a strong reflective effect and is highly visible in the dark. Running arm lights make your nighttime exercise safer and more convenient. ADJUSTABLE SIZE LED RUNNING ARMSTRAP: The size of the runner's running armband light can be adjusted from 28 to 32 cm with Velcro buckle design to fit most men, women and children. To use, you just need to adjust it to the right position and wear it on your wrist, arm, or ankle. RECHARGEABLE BATTERY: Our LED running armband comes with two USB charging cables and is rechargeable, no need to replace batteries. This reflective armband LED can be used for 4-5 hours and charges in about 2 hours, so you don't need to worry about running out of battery even if you are outdoors for a long time. Wide application: Runner arm strap running light is widely used in darkness, night, rain, fog, cloudy and other low visibility conditions, perfect for men women and children cycling, jogging, dog walking, mountain climbing, running and camping