bike seat bag There are two categories of seat bag users: seat roll enthusiasts and seat bag users. Traditionally, seat bags have been simple open spaces that allow the contents to slosh around, make noise and rub against each other. Often, the spare tube stored in the seat bag has more holes than the tube to be replaced due to friction with house keys or multi-tools. We designed a book-like layout where the bag can be fully opened to keep the tubes and CO2 cartridges on one side, separated by padded ballistic nylon "pages", and the other side to store the inflator head, multi-tool, contact lenses box etc. The "page" or divider also contains a pocket for credit cards, ID, money or house keys. The zipper allows the case to fully open and lay flat when off the bike, while also providing easy access to the multi-tool and money/card slot while on the bike without risking spilling all the contents of the bag.