Balystik set of 2 Enhanced spring for AEG M4 hop-up unit

Those springs are harder than usual. Once the uppper receiver fitted, they will lock & tackle your hop-up unit on the front of the gearbox to ensure perfect seal & no movement during firing.

Set of 2 springs :

• 1 x spring central heavy force Spring for M4 AEG hop-up unit
• 1 x Enhanced strong spring for M4 AEG hop-up unit

Note the Prowin hop-up Unit showed on the pictures is for demo only and not included in the package.