This bolt is for racks that mount on cantilever brake bosses (like the Nitto Highrider). That's the "clean, tidy, Franco-Japaneso" way to mount certain racks, and I can't say I've ever seen or heard of a brake boss snapping off due to any extra stress that came about from having to do double-duty as a rack mounting point. But it still bothers me a little. In the case of the Nitto Highrider, we provide provisions for mounting it to the bike in six to seven different places (depending on your bike), and the idea of sharing the load like that seems good. A cleaner and perhaps safer alternative to just using the brake bolt by itself. Sold per pair.