The F5 Storm Shelter STANDARD line is a great shelter for the money. Our STANDARD line shelters are at the top in the industry. Engineered to withstand 250 MPH plus winds. Our shelters are completely fabricated from steel and fully coated with up to 100 year plus rust protection. F5 Storm Shelters, Inc. has engineered and tested an all steel storm shelter capable of withstanding a category F5 tornado. An F5 Storm Shelter also has a fully integrated shelving system and up to five times more ventilation than our competitors.