Namsan LED High Visibility Armband,Safely Flashing Armband for Walking/Running,Children Safe,Night Cycling Jogging,Outdoor Hip-Hop Performances Props Bracelet,7 Colors Available Size: Length: 28-31cm(11 inches-12 inches). the armbands make easy to adjust for a loose or snug fit. Replaceable Battery: Take the CR1023 batteries, battery life: 60-80 hours, normal 2-3 months. Flashing modes: Fast flashing / Slow flashing / Continuous Material: nylon material, SUPER light, comfortable, soft, easy to use, user-friendly, real well-thought-out design and multi-function. Apply to children, adults and pets. Fits for outdoor sports safety, night jogging, running, hiking, cycling and all outdoor activities in the night