This specimen includes further improvements compared to earlier "I" or "II" versions.

British MK-2 visor reshaped to match and not interfere with A-13/ MS22001 oxygen mask and cast oxygen mask receivers;

Cast oxygen mask receiver installation;   

Single plug comm connector.

Rear comm cable exit supplemental leather hose fitted in order to bend the cable to the left; 

Replacing the A-14 mask, the A-13/ MS22001 oxygen mask was introduced, modified  with a supplemental diluter valve;

Boom mike "banana mount" installed.

More on H-5 HERE

MS22001 oxy mask compatible with the DH-115 (British) oxygen system, fitted with the connector for bailout oxygen bottle.

Night flying was trained in DH-115 Vampires, by student wearing Polaroid M-1944 goggles with blue lens and the aircraft fitted with an orange colored canopy. This combination prevented the view to the exterior.