ALG Defense AK Main Spring - High Engery Black. It is a Chrome Silicon single wire spring fabricated per ASTM A401 specifications. The ALG High Energy Mainspring develops 25percent more torque over a standard factory main spring lowering lock time and also increasing the consistency of primer ignition. Specifications for ALG Defense AK High Engery Main Spring: Manufacturer: ALG Defense Color: Black Gun Model: AK-74 AK-47 Additional Features: High Energy 25percent more torque Package Contents: ALG Defense AK High Engery Main Spring What firearm models does the manufacturer say ALG Defense AK High Engery Main Spring is compatible with? The manufacturer says that ALG Defense AK High Engery Main Spring is compatible with AK-47 AK-74ALG Defense 04-233-F: AK Main Spring - High Engery