Ukrainian airsoft shop, Strike Shop, talks about the ESA quick spring change system of Specna Arms... "The ESA quick-change spring system allows you to quickly adjust the drive to the conditions of the test site without using a large list of tools. 4 minutes will be enough for this. During this time, it will be necessary to unscrew the butt tube and replace the spring, without removing the gearbox.
The attractive price of Specna Arms actuators, combined with an innovative spring change system and high-quality materials, make this weapon suitable for both beginners and experienced airsoft players.

And yes, if you have a drive from Specna Arms of the CORE, EDGE or FLEX line and want to adapt it to SQB, you should prepare:

1. A long Phillips screwdriver
2. Hexagon

With all this at hand and good lighting, you can begin:

• we take out the battery and the case,
• we unscrew the fastening screw in the butt tube,
• remove the butt tube,
• press and scroll the guide until it comes out,
• remove the spring guide and the spring itself,
• we replace the spring.

This allows you to quickly and efficiently adjust the power to the required conditions without the need to use a number of tools.
The benefits of Specna Arms' ESA system cannot be overstated. The system guarantees the user significant opportunities and more free time for tasks. Allows you to replace the main spring in a minimum time.

Everything that sometimes seems too complicated has a simple way to solve the problem."