Bought for use on my van's roof to hold a 9'1 longboard - already had roof bars up there which turned out to be too thick for the supplied fixings but wasn't too difficult to make it work. Really quick and easy to use. Haven't tried it with two boards but, as some of the other reviews say, it could be a bit tight to fit another board in with the size of strap supplied.
Thule Stacker Kayak Carrier Reviewed by Lisa J (Osceola, WI) — 2011-08-24 13:05:08 We were able to easily mount two sets of the Thule Stacker on the factory roof racks on our mini van, and easily carried our three kayaks that way. The tie down straps worked very well, and getting the kayaks on and off was easy. VIEW MORE REVIEWSShop Thule Stacker Kayak Carrier | Shop Thule
Thule’s number one priority is safety – for you and the people around you. Our fit kits ensure your roof rack fits your car as safely and securely as possible. Also, at the Thule Test Center™, our products are only given the official seal of approval once they’ve survived numerous crash tests, wear and tear simulations, as well as extreme heat, cold, damp, sunlight and even harsh chemicals. All so you’re free to concentrate on the adventures ahead.