The Mido (pronounced ‘Mee doe’) Ocean Star reference 5907, part of the Ocean Star Series, was apparently released in 1961 (though other information dated the introduction 1959/1960, possibly due to the initial Ocean Star series release in 1959) through 1965. The most common dial variant Mido ref 5907, known also as the “Rainbow Diver” and “Powerwind 1000”, features a colorful “exotic” dial, with bright concentric rings highlighting decompression times for depths down to 149 feet.
The “deep dive timer”, as it was called in Mido marketing materials, was produced with different color backgrounds against the “rainbow” dials, in feet and metres versions, date and no-date, and in enough combinations of tension ring color and lume plots that many of the remaining reference 5907s are seemingly unique in configuration.
Please note that this research of the Mido 5907 focuses exclusively on the colorful “rainbow” dial examples. Beyond this dial design we also see an all black dial ref 5907 on occasion. Although I do not follow these, the only examples I know of feature ‘Mido’ printed on the dial, with ‘OCEAN STAR’ text below the center post, ‘SWISS T’ and ‘< 25 mc' at the bottom at 6 o'clock, and black date. These I see in the 305xxxx serial range. Special shout-out to Justin Vrakas at watchsteez for the assistance. Thanks!