I have seen two types of movements, both automatic, to date:
1. On earlier (2210xxx) non-date pieces: Mido 917PO (18,000bph, 12″, for Ocean Star pieces, base plate AS 1131/1132)
2. On later (3050xxx) date pieces: Mido 1137 OC (19,800bph, 13″ for Ocean Star pieces, base plate AS 1717; related technical details as with the 1147OC)
Some sites will reference the Mido using a caliber 619, but I have never seen such a movement in a Mido 5907, nor elsewhere.
