Xlab aero tt v2 cage bottle prevents bottles launching under extreme conditions including mountain biking and rough road surfaces features save up to 20 seconds off 40km tttri 25 less drag than round bottles special xlab hi grip deep pocket cage thicker polyethylene to avoid distortion from hi grip carbon cage some areas are completely covered with a non slip surface easy grip groove makes it easy to withdraw from hi grip cage material taste free bpa free polyethylene weight 90g