Mk13 Stores Ref: 6D/2253341 | Martin Baker Part No: MBEU/72396
The Mk13 PEC was only used for Hawk and RN Sea Harrier.
A "Fighter Type" PEC for low altitude, it provided connections for: breathing oxygen, anti-G trousers, and communications. The Mk13 is also fitted with an "Anti-Drown" Valve.
This image shows a Mk13 PEC. Clearly visible is the anti-drown valve.