Increase the fps/power of your rifle exactly to the legal limit of your field with the fps adjuster rings. You can put them on the spring guide to adjust the muzzle velocity of your SSR4. The package contains 2 rings. 1 FPS adjuster ring will increase power by 0.15J, on average, and you can stack a maximum of 2 rings. ONLY use together with original SSR4 Springs Do not use any adjuster rings if the power is already at or above 1.5J
