One Rail kit: This rail attachment replaces our standard vertical bike rack rail and allows up to one bike to fit with up to 4 1/2" wide tires to strap right on the new rails. Each patented vertical bike rack kit comes with all hardware, large steel wheel hook, and straps. Installation instructions included. (fits one bike) This is made from rust proof aluminum 3/16" thick. Up to two Fat tire rails can be added. Very heavy duty to protect your valuable bike.