According to our research the Red Depth Explorer 6610, was only made in a small batch on the first year of its release in 1955/1956, as most examples that have appeared also started in serials 113xxx, indicating how small the production must have been. Antiquorum has only sold 1 other similar example that is only 13 case numbers apart from this example. Kept in very good overall condition, with a near mint gilt dial reacting strongly to the Geiger counter, a beautiful and rare example of these "Red Depth" watches.