The standard design is universal and will mount to almost any load bar or luggage rack on vehicles today. Each set is designed to transport kayaks on their side, saving space and allowing you transport 2 kayaks on one vehicle. Heavy duty, non medical grade, Stainless Steel design has memory foam padding to protect your kayaks and provide years of trouble free service. Racks have added vent holes to extend the product service life. The large "J" style design makes loading and unloading fast and easy.Racks will accept kayaks up to 3 feet wide and weighing up to 100 pounds. Racks will easily fit most factory and after market square, oval, or flat cross bars. Fits crossbars that are up to 3-1/2" wide square or rectangle. Fits crossbars 1-1/2" at least in diameter for oval. Crossbars run from the driver side of the vehicle to the passenger side. Racks will not fit on bars that run from the front of the vehicle to the back of the vehicle. Come with 2 different sets of bottom mounting plates one curved and one straight (flat), depending on your need. All mounting hardware is provided. Included are the quick adjust hull tie down straps, and the bow/stern tie down ropes for added transportation safety.Fold down racks when not in use so you do not hit things such as drive-thru awnings, fully opened garage doors, etc. Only about 6-1/2" high when folded down. When not in use fold down for better fuel mileage.View an installation video on youtube. US Patent Registration # 29-596084