USB Charging Night Running Led Armband Outdoor Cycling Jogging Arm Strap Bike Safety Light Reflective Belt Warning Wristband Description: Size:35cm*2.5cm Switch Box:3.5cm*2.5cm HOOK & LOOP Size:12cm*2.5cm Adjustable extent:27cm-31cm Charging method:USB Multi-colors led lights, practical and cool to arm yourself when moving. Magic strap closure, easy and convenient to wear and remove. Can be tied around your wrist, arm, leg, bikes as a warning light. Four modes, best meet your demands. Great for outdoor sports, night running, large-scale festival party, concert, promotion, etc. Package include: 1 x Arm Leg Lights NOTE: This is a New Upgrade type,it can be charged by USB. Question: 1: Do you need to replace the battery? A: NO.this is a USB charging armband. 2: What is the flash mode? A: Flash, slow flash, long light, off. Fourth gear 3: How long can I use? It can be used for about 2 hours after charging for 20 minutes. Can be charged repeatedly