Very rare RAF Supermarine Spitfire RPM indicator Mark IX cockpit gauge dated 1940 in the Battle of Britain period. This is an exceptionally rare and highly sought after part. This is the 4000rpm version from the earlier built Spitfires being replaced by the 5000rpm versions. At 86 years old, it shows expected significant wear and ageing. The white paint on the RPM needle has crumbled a little as can be seen in the last photo.