This confirmation was also a first, as laboratory experts had never before issued such a certificate.
Each model is a unique addition to the overall series.
The Seamaster 300 quickly gained a good reputation among professional divers.
Many divers from the civil and military sectors chose to wear this watch, as well as the UK Royal Navy's Special Boat Service.
Generally, diving watches should regularly have their waterproofness checked.
If there's no confirmation that a pre-owned Seamaster has recently been checked when you're purchasing one, then you should take it to be serviced.