A.P.S. Hammer Spring for ACP601 GBB Pistol 
Essential part for upgrading your Airsoft AEG Hammer Spring Set 
To build a tight & durable gearbox 
Replacement of gearbox internal springs 
This Hammer spring is very strong 
It is designed for APS ACP601 Pistol Use 
Suitable for ACP601 Series Airsoft Gas Blow Back GBB Pistol