Unequal Upgraded Spring Kit For SRB Series

How to upgrade

Use a screwdriver to disassemble the gun body casing, rotate the button at the back of the gearbox, remove the original spring, and replace it with a new one. Upgrading the firing rate is effortless!

With the spring FXT WORKS provided, enjoy reliable performance at 250-270 fps for the SRB400 / SRB400-SUB / SRB1200 / SRB375M.