This is a stainless steel guide rod for a Smith and Wesson SW9F / SW40F made out of 304 stainless steel. The rod is made of only the finest stainless steel material to replace the plastic factory rod in your Smith & Wesson SW9F / SW40F. Our rods are measured to factory specification and we ensure the finest fit and finish on all of our parts. This is a great upgrade to the guide rod in your Smith and Wesson SW9F / SW40F for reliability. Spring is now included and drop in ready.