Crafted from top-tier, drawn and tempered chrome silicon wire, this product exemplifies superior performance and unmatched durability. Each unit undergoes rigorous testing to ensure it meets the highest standards of reliability and efficiency. The 19.5 lb hammer spring (mainspring) is engineered to enhance your pistol's cycling capabilities, providing consistent ignition and enabling a smoother, lighter trigger pull. This combination of quality materials and meticulous testing guarantees a product that not only meets but exceeds expectations in both performance and longevity. Chromium-silicon wire Stress relieved Manufactured in the USA