Mk9A Stores Ref: 6D/2253044 | Martin Baker Part No: MBEU/55745
The Mk9A PEC was only used in the RAF for Buccaneer S2.
A "Fighter Type" PEC for low altitude, it provided connections for: breathing oxygen, anti-G trousers, and communications. The Mk9A is also fitted with an "Anti-Drown" Valve. The AVS bush, while present is capped off and not used.
The bayonet Mk7A oxygen connector has a fitting to attach it vertically to a later LSJ chest plate.
Also included is a lanyard to save the PEC plate clunking on the cockpit access ladders. Mod PE58 added an additional lanyard around the oxygen hose as can be seen below, to further help steady the PEC plate on entering / exiting the cockpit.
This image shows a Mk9A PEC. Clearly visible is the anti-drown valve and cap over the AVS fitting.