Kit includes 7 springs from Wolff Gunsprings..... Five Firing Pin Springs, One extra pwr ( 6# ) Trigger Spring, and One reduced pwr Firing Pin Safety Plunger Spring ... The Firing Pin Springs are different weights ... 4.0#,4.5#, 5.0#, 5.5#, and 6.0#.... Stock FP weight is 5.5# ... If you want the lightest trigger pull, use the 4.0# FP spring. The 6.0# FP spring will give the the strongest primer hits... Some Glocks struggle with light primer hits using the 4.0# springs. Increasing the spring weight to the 4.5 5.0 or 5.5 should eliminate the light primer strikes while maintaining the lower weight triggers...... Using weak primered Ammo will increase light primer strikes.