Springs for your AEG replica of brands like Guarder, Prometheus, and element. We have many types of springs like the M90, M100, M110, M120 etc
The spring in your airsoft device ensures that air pressure is built up in the cylinder, using the piston, pistonhead etc.
Springs are available in various types and strengths such as M90, m100, m110 etc. Guarder uses for example SP instead of M but the values between SP100 and M100 are almost the same. Often we get the question which spring comes standard in a airsoft gun, this is almost never known because this is unfortunately not mentioned in the manual of a airsoft gun. If you want tyo change your rpsing to a more powerfull one, we normally recommend the M100 and M110.