Leg kits are used when its necessary to span over rough terrain and blocking is not practical. Each kit comes with 2 – 3 ft long legs of 1 1/2 inch aluminum schedule 80 pipe along with the bracing and hardware necessary. Requires the use of a drill and 1/2″ drill bit to custom locate and plumb the legs. Rails should be supported about every 9 feet for boats under 2000 lbs and about every 4 1/2 feet for boats over 2000 lbs. Comes with 12 inch square foot plate for the base of the leg.