The hook-and-loop saddle attachment keeps the bag firmly connected to your bike;The low-profile seatpost attachment prevents the bag from swinging while riding;Internal pockets securely hold credit cards and valuables;The loop on the front of the bag easily attaches clips for rear lights;A zipped expansion area allows for extra storage space;The light and robust material holds up to elements without contaminating contents;1.7-litre (105 cu in) capacity - 2.23-litre (142 cu in) capacity when expanded;