M135 spring for VSR-10 sniper rifles
This spring is made of high quality spring steel and is suitable for TM VSR-10 rifles and its copies. It is designed for 7 mm spring guides. The "M135" indicate an approximate muzzle velocity of 0.2 g BB - 135 m/s (440 fps). In the case of good sealing and composition of the weapon, the muzzle velocity may be higher.
SLONG Airsoft
is an airsoft manufacturer in Taiwan producing spare, upgrade parts and accessories such as hop-up chambers, inner barrels, motors, connectors, wiring, parts for gearbox and even outer parts such as handguards and stocks, so you can make a complete AEG just using parts from them. In 2020 SLONG Airsoft released its own M4 AEG rifle.