The Plan B Micron is a scaled down version of thePlan B. This discreet unit mounts under the saddle and around the rails using a 25mm strap with a clever magnetic hook to secure it. The PU coated zip and 1000D nylon construction makes the Plan B Micron water resistant, the 300D liner backs this up. There are 2 HD elastic loops inside for stowing a multi tool and a CO2 canister leaving just enough room for a spare road tube and tyre levers. The Plan B Micron carries bare minimum spares, you could probably squeeze your front door key in there too.