Xlab stealth pocket 400strap mounted bag for integrated stems or cables entering top tube holds typically 6 gels low 23 inches high features more aerodynamic actually reduces drag caused by stem and headset spacers airfoil shape provides clean air flow around bag perfect 51 ratio for lowest possible drag same width as head tube therefore no increase in frontal area super smooth low skin friction exterior reduces drag non sway design non slip surface underneath bag grips top tube with