CNC Short Stroke steel gears with a 13:1 gear ratio. The sector gear has 12 teeth, which reduces piston cycle time. The spring is compressed to a lesser degree, resulting in reduced FPS. Recommended for V2, V3 and other gearboxes that use standard AEG gears (M4, AK, P90, G36, MP5, etc.) with M120 or weaker spring.