Dynamic Precision have mad a new kind of Recoil Spring in 2 different editions.
This one is the "Speed Master" which is designed not to give the wildest recoil, but to give a better control when shooting.
These Recoil Springs are made of spring steel. The Non Linear spring design with a special calculated number of coils gives a more precise control on the recoil speed and better tuning for different slides.
There are 2 springs in the package.