Stores Ref: 6D/2253045 | Martin Baker Part No: MBEU/55744
The Mk1A PEC was only used in the RAF for all Mks of Lightning, Canberra PR9 and B(I)12, and Victor K2.
A "Fighter Type" PEC for low altitude, it provided connections for: breathing oxygen, AVS, anti-G trousers, and communications. Similar to the Mk1, but with the addition of the anti-drown valve.
This image shows a Mk1A PEC. Clearly visible is the anti-drown valve at the base of the oxygen hose.