Caliber 515.24

The 11½-ligne sibling of the 505.24 in Ronda's xtratech line: the same GMT quartz with hours, minutes, seconds, a date and a quick-set 24-hour indication, the same 3 mm height, one jewel in both the Swiss Made and Swiss Parts versions, 45 months on a 371 cell (60 on a 395) and a rate of minus 10 to plus 20 seconds a month, in a larger 25.6 mm case fitting. Ronda makes it with a 24-hour hand (515.24H) or a 24-hour disc (515.24D) and publishes identical figures for both; this row is the calibre as slow names it, with no suffix, and the catalogue's separate 515.24D row is the disc execution other houses name. slow uses it in the Round and Round-S, where the single hand is the one that turns once a day.