One set is already included with each carrier when you select "Rack" strap option.
Purchase an extra set if your car has side rails and cross bars.
Or if your car has only side rails or only cross bars: use 4 parallel straps for added attachment strength.
Straps attach to side rail or cross bar by means of a slip knot using the loop at each end of each strap.
Straps go over the top of the carrier, passing through strap guides.
Set includes two straps.
Each strap has 3 components: Rack Short Strap + Top Strap + Rack Long Strap.
Total length per strap: 98 inches.
Add extra Rack Straps if :
(straps are interchangeable)
One set included with carrier for car "WITH RACK"