Features: LED lighting design provides high brightness visibility, effectively enhancing the safety of nighttime sports. Suitable for night running, cycling and other scenarios, allowing you to be clearly identified even in dim environments, reducing the risk of accidents. Comfortable fit, without feel of restraint when worn, and not prone to discomfort even after prolonged use. Convenient for quickly turning on or off LED lights, without the need for tedious operate. Not limited to sports protective gear, it can also be used for various occasions such as outdoor camping and hiking. Specifications: Component: Reflective crystal lattice, LED light group, elastic band, 2032 button battery Size: Adjustable length, suitable for different arm circumferences Attribute: refer pictures to selection please Practicality: Suitable for night running, cycling, hiking and other outdoor sports to enhancing safety and visibility Package Includes: 1Pc LED Glowing Reflective Arm Strap 1Pc Instruction Manual note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.