Portabrace Hard Cases (models ending with 50F) have a cubed-foam interior. Wheeled Hard Cases have durable aluminum rail and a comfortable pullout hand grip. They are constructed with a high-performance hard-resin material reinforced at the corners. Wheeled Hard Cases are smooth rolling, have a pressure relief valve and have easy to operate latches. Wheeled hard cases are ideal for combining video, audio, and photographic equipment for transportation and protection. Please note: the PB-285OR is not a watertight / airtight case due to the process of adding the custom off-road wheels and axle. The case does not lose any protective strength or integrity but it will allow air to the main storage area.