Airspeed Indicator 450+ Knots MK 9L Ref 6A/4721 RAF. Spitfire Seafire
This is an excellent example of a post WWII-era Air Speed Indicator Mark 9L, Ref 6A/4721, as used in the British RAF fighters Supermarine Spitfire and Seafire.
Gauge still has its serviceable tag attached which is dated 1962 whilst the gauge itself appears to be dated 1952. Short cased version with various stamps on the rear. Made by Mechanism Ltd of Croydon.
As can be seen from the photos the gauge is in excellent condition. The gauge would need to be assessed by a suitably qualified person before been considered for flight use