ROLEX

Steel case with push-buttons and screw-down case back, Valejoux 23 base hand-wound chronograph movement.
Serial number 386894 engraved between the lugs at 6 o'clock. Reference inside the case back.
Case diameter 35 mm, from lug to lug 41 mm

Rolex chronograph reference 3525, circa 1945, steel case with pump pushers and screw-down case back, manual-winding chronograph movement based on the Valjoux 23, reprinted dial, and external case back engravings abraded/erased.
The reference 3525 was introduced in 1939. It’s not the first chronograph produced by Rolex, but likely the first Rolex chronograph with an Oyster case. This model has several nicknames: "Monoblocco," "Barilotto," and "Prisoner of War." The first two are easy to understand, while the third will be explained shortly. "Barilotto" means "keg," named for its barrel-like case shape. The term "Monoblocco" may surprise those who associate it only with the Royal Oak, but here it refers to the fact that the case, lugs, and bezel are all forged from a single piece of steel. This construction, quite rare for its time, is still unusual today.
At the start of World War II, Royal Air Force pilots bought Rolex watches to replace their standard-issue ones. When they were captured, these watches were confiscated. Hans Wilsdorf, founder of Rolex, ordered his company to allow prisoners of war to order Rolex watches while imprisoned, allowing them to pay later based solely on their word. This initiative boosted morale among the prisoners and increased Rolex’s reputation among American soldiers.