Each center fire ammunition manufacturer uses a primer cup and some primer cups are harder than others. This extra power striker spring for the XD Slim models is heavier than the factory spring, putting more tension on the striker allowing for more striking power on the primer for positive ignition.
For use will all ammunition regardless of brand.
WARNING: This product can expose you to Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to – www.P65Warnings.ca.gov