Factory Sig Sauer Short Reset Trigger (SRT) kits. This modification reduces the trigger bar reset by up to 60% over the standard reset. This allows for faster shooting due to the decrease in forward travel after the first double action shot is fired. This kit will only work on the models specified and DA/SA guns only. Will not work on pistols with a double action only or DAK trigger system. Gunsmith or Certified Sig Sauer Armorer installation is recommended.