Orion gearbox is a result of several years of Specna Arms experience in the field of internal parts. This product stands for reliability, durability and battle-tested solutions from the top shelf.

Steel gears and tooth rack along with reinforced gearbox shell provide the higher level of durability for stock spring as well as further, power tuning.

It's hard to imagine an easier and quicker way to change the spring. The ESA2 requires no tools and allows you to change the spring in less than a minute. Just remove the buffer tube, unscrew the spring guide and it's done!

ESA2 allows you to quickly adjust the muzzle velocity while being in the field. You can adapt your replica to indoor or field airsoft games in a second.