Can anyone id this PEC?

Hi All,

Can anyone shed any light onto the id of this PEC? What seat or aircraft type would it be found in.

The details on the unit are;
On the oxy hose – ?AS5231/F/60 – Iss 7
Batch No 7225B
Cure date 3/Q/76 (I understand this to mean 3rd Quarter 1976)
32C/701

On the base – Hymatic, Redditch, England
Part MSC 201 (0?)
Serial No PB352
Issue 1

In an engraved circle F8 – 240

[ATTACH=CONFIG]224536[/ATTACH][ATTACH=CONFIG]224537[/ATTACH]

Many thanks

Nigel (owner Sea King XV677)