This Op Rod for the Piston System is made from H-13 tool steel which is machined and nitrided (polished stainless steel in appearance) to Superlative Arms specifications. Op rod and spring included.
NOTE: The op rod spring is not required to safely operate the piston system. We do not use these springs on our personal builds, military or law enforcement builds. We have done a 10,000 round torture test without the op rod spring resulting in zero failures. This is just a mag release spring that helps eliminate the small amount of rattle the op rod has inside the gas block. This spring will fail at a certain point and will need to be replaced. You should inspect your spring after each use if you choose to use it.