Enhanced compatibility Ultrathin structure aligns with bike frames, maximizing storage space without impeding leg movement. Designed for demanding cyclists who need extra capacity without sacrificing ride feel. Dynamic balance Calculated distribution of pressure zones keeps the upper tube bag in its ideal position, even on technical descents and sharp turns. Maintains stability and access to contents during challenging riding. Practical biside design Side pockets provide organized storage for purses, face masks and electronic accessories. Weatherproof design Fully sealed seams, performance waterproof coating and integrated seam runners deliver reliable defense against extreme precipitation. Use scenarios Longdistance road rides where compact, unobtrusive storage is required and quick access to essentials matters. Mountain or gravel descents and tight cornering where bag stability and position are critical. Daily commuting in variable or wet weather, keeping purses, masks and electronics protected and dry.