Main Spring Set, Trigger Return Spring Set, Sear Spring Set, and Valve Spring Set Spring force can be easily seen from the number of coils on the spring. Less coils is stronger, more coils is weaker) (1-5 is from left to right for each picture) - Top Left : We recommend using Main Spring #2 or #3 initially (#2 will give higher velocity) - Top Right : We recommend using Trigger return spring #2 initially (#3 requires a very well tuned gun and frame or will not work) - Bottom Left : We recommend sear spring #3 (Light Medium) but if the hammer skips you may need a stronger spring (common for older marker with heavier hammer springs.) - Bottom Right : We recommmend Valve Spring #3 initially