The Specna Arms PRIME™ AR15 model lower frame is made of all-metal and is compatible with the ESA2.1™ (2024) quick-change spring system. The updated quick-change spring system significantly improves the durability of the rear part of the lower frame compared to the ESA 2.0 model.
The frame is fully compatible with Edge and Edge 2.0 series upper frames, but requires a separate ESA2.1 spring guide (2024).
Compatible spring guide:
https://www.atom-airsoft.fi/tuote/specna-arms-esa-2-1-jousenohajanin-prime-2024/
