This is the Steel helium escape valve fitted to the majority of Seamaster watches (not Planet Ocean).
These are Omega supplied service HE valves for many calibres.
Case References from 2008 onwards but will fit older models, 36.25 mid size and 41mm full size.
It replaces the 086ST0061 model HE valve.
Omega Seamaster Watch 086STZ000506 Helium Escape Valve Steel
Items can only be returned if either faulty, in the case of the item not being required then it must be returned exactly as received. For example if the item is new in a sealed packet and/or has protective covers in place then it must be returned the same otherwise item is no longer new and the value is greatly reduced, these items can only be returned/refunded by agreeing a lower value with Swiss Limited Editions before returning reflecting the new lower value of the item.