The Mission Saddle Bag attaches to any Road, MTB, or Gravel bike seat and is compatible with all dropper posts. Constructed using waterproof Dimension Polyant VX fabric and Hypalon, the saddle bag is highly weather resistant and quick drying. The compact design is outfitted with a YKK Aquaguard zipper and four internal elastic pockets to keep your tools stable and organized.In addition to the seat attachment, the wide Hypalon straps also attach securely to most bike frames (top tube or down tube) providing extra storage as needed.