Exterior: Our seat bag has a sleek black finish with reflective graphics that allow the bike seat bag to virtually disappear under the saddle while still having a reflective SILCA shield that provides high visibility in low light when seen by headlights.Interior: It has hi-contrast red nylon material providing full volume with elastic walls that protects to the contents. and having an asymetric design that keeps contents contained when the bag is fully opened.Volume: The Mattone bicycle saddle bag holds one inner tube, one CO2 cartridge, SILCA bike tire lever set, CO2 regulator head, credit card/ID, and multitool with ease.Attachment: Our bags have a BOA closure system with an open guide release on the Hypalon retaining strap, which allows for easy installation over the seat rails while providing industry-leading grip and strength in the steel cabled BOA closure system.Zipper: The YKK Aquaguard zipper is the top of the line in waterproof bag zippers that blends nicely with the overall design of the bike bags and allows the bike tool bag to be accessed while still being installed under the bike seat.