This is a special bag which can be mounted on a bike to hold a mobile phone. It is waterproof so the phone will not get wet and with the see through cover you can still see it and use the phone through it. So great for using GPS, maps and answering the phone when on the move. It is a compact size so does not get in the way and has a space for earphones or charger cables through the bag. It fits with Velcro straps which hold it tightly in place but make it easy to remove as well.