Prometheus Upgrade Spring

A non-linear spring features coils with varying spacing, which helps reduce stress on your gearbox during the initial compression phase. This design promotes smoother operation, less wear on internal components, and more consistent muzzle velocity shot-to-shot.

Yes, this spring is designed for standard Tokyo Marui-spec gearboxes. It is compatible with most major brands like EMG, Matrix, and other manufacturers that follow the standard TM gearbox architecture.

Prometheus uses a color-coded system for their springs, which makes identification immediate. You won't need to guess the rating or test it against other springs; just check the color against the manufacturer's chart to confirm the strength.

The 360 FPS rating is an approximation based on a standard test setup. Your actual muzzle velocity will vary depending on your specific air seal, barrel length, and hop-up configuration.

While this spring is designed to be reliable, upgrading your spring can increase stress on your piston and gears. It is always good practice to ensure your piston, piston head, and gears are in good condition and properly shimmed before installing a higher-tension spring.