Xlab stealth pocket 500the stealth pocket 500 version has been designed specifically for bikes with internal cable routing and frames featuring two toptube screw inserts the unique design allows the bag to be attached securely and easily onto the top tube features actually reduces drag caused by stem and headset spacers airfoil shape provides clean air flow around bag same width as head tube therefore no increase in frontal area perfect 51 ratio for lowest possible drag super smooth low s