This is a highly collectable watch.  The Hamilton was part of the "Fab 4" watch brands that supplied Royal Navy Pilots post war.  However, it is the most recognisable brand with heritage in the US military but was the shortest used.  It had production run only from 1970 to 1972.  King Charles III was issued his when flying helicopters in the Royal Navy in 1972.  
You can see by the photograph the King wearing his Hamilton - which he does when visiting or on duty with the Royal Navy.
What makes this watch stand out is it still has its original leather strap, whilst most perished and wearer would adopt a NATO strap (as King Charles did).
The watch comes directly from an ex Fighter Pilots collection and saw action in 899 Squadron on board HMS Eagle which was the sister ship of HMS Ark Royal.  It was decommissioned in 1972.  So this watch was one of the last to fly from that illustrious ship.
The dial is in perfect condition, lume still works and fully serviced and working perfectly.   A true collectors item.