Designed for motion: a lightweight ergonomic shape sits snugly on your back, reducing bounce and friction during running or biking for all day comfort on trail runs, marathons, camping, treks, or long distance cycling. Hydration on demand: builtin sleeve accommodates hydration bladders or water bottles, so you can stay refreshed without slowing down while moving during outdoor workouts or adventures. Reflective safety: integrated reflective detailing enhances visibility in low light, helping with early morning runs, late night rides, or twilight hikes by alerting nearby drivers and other trail users to your presence. Use scenarios Trail runs and marathons: keep bounce to a minimum with a secure, closetoback fit that remains comfortable over long distances and uneven terrain. Long distance cycling and outdoor training: stay hydrated on the go with a sleeve that fits hydration options, ensuring you can drink without sacrificing pace or form. Camping, trekking, and twilight outings: enjoy stable support and added visibility during extended wear in low light conditions. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.