The Mido 1137O watch movement is a detached manual wind movement, with a frequency of either 18,000 or 21,600 A/h. While the 558 movement is not officially cataloged, only samples with a frequency of 21,600 A/h are known. The reason for the signature HJP instead of HPP on these samples remains unknown. The differences between the 451 and 461 movements are not specified. The movement incorporates several functions, including automatic winding, sweep seconds, and a calendar with the date set by changing 20-24 hours. The Mido 1137O movement was used around the period of 1970.