Notes: The 4139 was a mens stainless steel dress watch made in the 1940s and 1950s. The cases were usually basic stainless steel but some were sold with gold plating. The dial face is typically cream or white.

Mechanism: The Hunter 10 1/2 Superbalance was introduced in 1935 with Swiss patent 188077. This new model replaced the earlier Hunter 10 1/2's which were graded according to their timekeeping accuracy. The new series was only manufactured at a single quality point. Superbalance movements from the perios 1935 - 1945 were occasionally made with 16, 17 and even 18 jewels. In certain cases the endstones are enhanced with screwed chatons. In very rare cases, sapphires are used in place of rubies. The appearance of the text "Patented Superbalance" on the mechanism is the best indication that you are looking at a Superbalance and not a basic Hunter 10 1/2 (which are labeled "Prima", "Extra Prima" or "Ultra Prima". However, to confuse things, the Superbalances are also labeled '10 1/2" H'.

Family Notes: The Precision is one of the most overlooked Rolex models ever made. This series is unusual not only because they are dress watches, but also because most of Precision models are powered by a manual-winding movement.