This is a ALG Defense Spring, model 04-231.
The ALG AK recoil spring is a one of a kind design" it is manufactured from chrome silicon steel and resists impact shock and relaxation. The 2 to 3 dead coils in the center change the natural frequency of the spring" which prevents harmonics from damaging the spring and reducing its free length.
Features:
Chrome Silicon Steel
Resists Impact Shock
Extreme Durability
