Stores ref. 6D/108. 'Blanking Plate' or end-piece for the type D oxygen mask. This was fitted when no integral microphone was required and/or when the mask was used with a throatmicrophone. The lightly domed black painted alloy plate was provided with twin exhalation ports and covered in chamois. It attached to the mask in the same way as microphones via the hinge on the microphome mouting ring.
This example is in excellent condition with clear markings. The chamois appears to be original but it is impossible to be certain. Either way it is in very good condition with light soiling/rubbing only. These are suprisingly hard to find now. Stock code O19681.