Heres some pics of my Merlin Boost Gauge Collection.
15 years ago I had about 50 of them all NOS in Boxes.
Spitfire , Hurricane , Mosquito and Lancaster.
Over the years I sold them off to Restorers and Collectors , just kept a few for myself
Dated 1940 and 1944
Good Reference Photos if you ever come across these types.
I love em , Im still just a big kid ( with a mental problem ) just ask my Mrs