Evolution Gun Works EAA Firing Pin Stop Carbon Steel Blued Finish. This feature keeps the firing pin from locking back (as it should) and aids in preventing firing pin breakage. It is made from a proprietary black fiber filled Nylon. The proprietary stiffness of this new material compared to other fiber or Nylon firing pin stops allows it to withstand greater stress and withstand wear better than other fiber or Nylon types. It retains a very stout design while allowing the firing pin to rotate easier. The material we use does not come apart or shed. Superior to other fiber or Nylon stops this will not break or wear out. Specifications for Evolution Gun Works EAA Firing Pin Stop: Manufacturer: Evolution Gun Works Color: Black Package Contents: Evolution Gun Works EAA Firing Pin Stop Evolution Gun Works 20060: EAA Firing Pin Stop Carbon Steel Blued Finish