I've >heard< that they break at the weld on the mounting plates when seriously hit when coming off a rock. As long as they receive steady pressure (like the Hi-Lift bit) they work fine, but rock crawling translates into bashing the rockers. You will probably do better to get something which bolts directly to the rockers. I use Sun Performance rocker skids (pricy at ~$250). Dan Duffy at Off Your Rocker Panels (e-mail [email protected]) also has a stout setup for ~$150.