Rod end bearings are used on the ends of cylinders, linkages, rods, and shafts to take up angular misalignment between connected parts. They consist of a spherically-shaped inner ring and a cylindrical bore for shaft mounting. Metallic rod end bearings are made of brass, bronze, iron, or steel and often plated with zinc or chromium. Non-metallic products are made of plastic, nylon, or Teflon^®, a registered trademark of DuPont. Rod end bearings attach to rods and shafts via a male stud with external threads or a female housing with internal threads. Right-handed threads tighten in a clockwise direction and are the most commonly used type of thread. Left-handed threads tighten in a counterclockwise direction and must match the mating part. Load capacity and maximum angular misalignment are the most important specifications to consider. In most cases, bearing motion is symmetrical and the maximum angular misalignment is half of the total side-to-side range.