1. One- piece designed bolt carrier 2. Improved durable and strong steel material 3. Enhanced heavier recoil force feeling 4. Simulated and realistic 2 section wire rod type recoil spring assembly design. 5. Long stainless steel gas piston with length just like real AK’s part 6. Complete easy and fast Drop-in installation. 7. Features bolt full and half travel by preference or different game scenario.