These bars were really easy to fit to the Thule aerobar roofrack system. Slide the specially made bolts into the slots on the roofracks and use the nuts provided to attach the (very well made and solid looking) V bars to the roof bars. The recommended minimum gap was 90 cm but for a standard (nelo) k1 the bars need to be 105 cm apart and the (quality) bungees sit just in front and behind the cockpit. The kayak sits nicely in the bars and doesn't move around. The extra straps can be used to ensure the kayak doesn't move in the unlikely case the bungees break. I drove for over an hour and a half with the kayak on the bars on the first trip and it didn't move around at all, neither did I notice any appreciable wind noise.Two small complaints - one of the plastic plugs for the end of the bars was missing (see photo - I suspect from the factory), but these cost a couple of euros and are easy to replace. I also put the (provided) red warning flag on the end of the kayak, but as soon as I got on the motorway it slipped off, never to be seen again - if this could be developed so that there was eg. a velcro attachment system, it could be placed in front of the rudder to ensure it stays in place. Back to tying on lengths of red and white warning tape for me! Overall though, a very good product which will give years of service. ( I gave it five stars, but 4.75 would be the best because of the two issues above...)