This bag mounts directly to your luggage rack, sissy bar, or seat and is large enough to hold one full face helmet.; Industry leading UltraMax fabric for maximum UV-protection Mounts to luggage/tour trunk racks, sissy bar or seat using quick release and self-fastening straps Holds 1 full face helmets Lockable zippers Reflective piping for enhanced visibility Waterproof rain cover included Rigid construction and solid base panel prevents sagging Lifetime manufacturer warranty 31 liter capacity ( 40 liters expanded) Dimensions: 14" L x 13.5" W x 10" H (13"H expanded)