Which chronograph did NASA certify in 1965 as flight-qualified for all crewed space missions?

The story behind it

The Speedmaster was never designed for space: when it launched in 1957 its intended customers were racing drivers. It was also the first watch to put the tachymeter scale on the bezel rather than the dial. NASA invited four brands to submit chronographs, and the Speedmaster was the only one to survive the tests.