Topeak Weatherproof DynaWedge Seatbag. Features: A weatherproof seat pack made to battle the nastiest weather out there Standard model designed for road bikes and gear while the large size is more for mountain bikes and able to store a 29" tube Features water proof zippers and Topeak's Rail Wing system to securely attach the bag while also allowing for access Specs: Model:Weatherproof Dynawedge Mount:strap Size:large Capacity:37 cu in (0.6L) Dimensions:- Weight:- Color:black