I got these after checking compatibility with a karrite box. Yes they fit, but what a faff. You need to have them in exactly the right position, as they fouled the front lip, then I had to drill out more holes which compromised the strength of the box. This was due to my wing bars being on fixed points. I guess if you had moveable bars on rails, they'd be ok. However, even when fitted, they didn't make life any easier than when I had my old, cheap, secure u bolts!