13mm upgrade spring for TM VSR - 450 FPS (M135)

Upgrade spring for Tokyo Marui VSR and copies. With this spring, you can achieve a muzzle velocity of 450 FPS or 135 m/s. However, if the weapon is properly sealed and assembled, the muzlle velocity can be be higher.

• Springs are all "perfect" variable pitch, giving light compression and fast return. Some springs use a different "variable pitch", but that's just connect the some different pitchs.Those are difficult to compress and do not give the desired power.
• PDI uses silicon chrome steel to make the springs. Also, PDI can finely adjust the pitch using thissteel, so we can offer different power levels.
• Each spring may look different because our springs are individually made by skilled craftsman. Springs that provide the same power may be slightly longer or shorter.
• PDI's Springs don't shrink! Generally,spring will shrink from 15mm to 20mm.We can control under 13mm-5mm.

Notification: Outer diameter of this spring is 13mm and cannot be used for the original plastic pistons. Please use 9mm spring guide and pistin with the 13mm hole.