The Recta B watch movement, produced around 1955, is a manual wind movement that features a unique Incastar regulator. This regulator, the only one of its kind produced on a large scale, employs a free oscillating hairspring with its end fixed between two rollers. This mechanism allows for length adjustment of the hairspring, eliminating any isochronism error caused by the gap between the regulator pins. Additionally, the Recta B movement incorporates several functions including a sweep second hand, day and date indicators set by pushers at 4 o'clock, and a moon phase indicator set by a pusher at 8 o'clock.