The Apex Durable Striker for the FN 509 Series pistols is a direct drop-in replacement for the factory striker. This striker has been tested and certified for dryfire on an empty chamber up to 100k strikes. You read that right - certified for 125,000 dry strikes. This Striker is the culmination of over 3 years of continued R&D and testing. Through the R&D process, they've cataloged more than 1 million dry fires to prove out the design.