Valve-nest for Tokyo Marui M870 shotguns

This is our BST valve-nest for Tokyo Marui M870. The stock valve-nest isn't seal properly so we redesigned it with a lot nice and nice function.

- New sealing design. The valve-nest has much better and bigger contact are which cause better sealing even with HPA.

- It has a spring guide for the hammer spring.

- Made from copper by hand-working. The size is perfect, we spent a lot energy to reach the best design - this is the third version.

The third version tested with HPA, it is run 7 month without any leaking in TM Breacher.