The Raptors RTQ Extra Durable Japanese Steel M170 Upgrade Spring is a precision-machined upgrade component that can help increase the velocity and power of your airsoft gun. It is made from high-quality Japanese steel and features an M170 spring rating that is ideal for high-powered airsoft guns. This upgrade spring is compatible with most airsoft guns that use standard AEG gearboxes, and it can help improve the performance and accuracy of your gun.