RPM's rod ends have oversized hexes and our ball cups are molded to the strictest of tolerances & are molded from our blend of tough, bulletproof nylons. If you're tired of popping ball cups and breaking rod ends, RPM rod ends are the solution! RPM rod ends fit all Associated, Losi, & HPI ball-studs. Like all of our products, RPM rod ends are guaranteed not to break! Available in Bold Black, Dyeable White, Yellow, Blue, & Purple!.