HEPHAESTUS Enhanced Recoil Spring for Marui AK GBB Airsoft

Made of high quality oil tempered chrome silicon steel wire for durability Enhanced spring rate and length for best performance with Green Gas ( 12kg Gas or above ) Improve shooting experience and felt recoil Drop-in upgrade to replace stock Recoil Spring of Tokyo Marui AK GBB Series Remarks: Not suggested to use with HFC134A Gasies