Premium quality springs manufactured to ISO 9002 quality control standards from aerospace-grade chrome silicon steel for consistent, reliable performance and superior durability. Your trigger pull feels better, and your gun performs consistently and reliably. These springs maintain a constant compression rate so they don t stack as spring tension increases. Heat treated, shot peened, and stress relieved to retain loading capability through thousands of compression cycles without taking a set. Trigger Rebound Spring provides a 10% reduced-power (approximately 16.2 lbs.) loading for a lighter, more consistent trigger pull from J, K and L frame revolvers. Hammer/Trigger Spring Pak adds a factory-weight hammer spring for consistent let-off and positive ignition.