I inherited this LeCoultre Master Mariner and will be looking to sell it, but I don't know what it is or how I will be able to describe it. I do not have the tools to open it to get more identification. Perhaps someone can give me an idea of what it is, when it was made, etc. from the photos. It is marked "10K Goldfilled" but I don't see any identifier. The buckle, the strap and the crown are all marked LeCoultre (or with its insignia). Thanks in advance for any clues here.