Features separated compartments with side and rear zippered entries . Medium is perfect for MTB tube/tools, small is great for Road tube/tools. Quick Release mount attaches to saddle rails, hardware included . Made from 1000 denier nylon with PTFE coating. 3M reflective strip and rear light attachment location. Features: 1000-denier Cordura Plus Fitting for taillight DX bag has an internal packet to keep tools away from delicate items DX bags have an internal pocket to keep tools away from delicate items