Longines - Automatic Ultra Chron Calibro 431 - No Reserve Price - Men - 1969

Fantastic and rare vintage watch from the 1960s (specifically 1969) for men, LONGINES (Swiss Made) model 'Automatic Ultra Chron'. Mechanical automatic movement, Caliber 431, perfectly functioning.
35mm gold-plated case excluding crown; gold-colored dial. Date window at 3 o'clock and original Longines logo crown.
The case back bears the inscription 'Use 1175 Wrench,' indicating that this type of key must be used to remove the crystal and access the movement from the front.
Assemble an elegant and valuable new leather strap measuring 23cm.

Information about the rare and valuable movement of this splendid watch, namely the CALIBRO 431.
The Longines 431 caliber was introduced by Longines in 1967.
It is a mechanical movement with automatic winding and central seconds.
It has a semi-quick date setting device, meaning that at midnight, you need to turn the hands back to 10 PM and then forward to midnight.
The balance oscillates at a frequency of 36,000 a/h, therefore it is considered a 'high frequency'.
It is also equipped with a flat compensating spiral and adjusted using an eccentric screw wrench.
Train lubrication occurs dry with molybdenum disulfide, a consequence of high frequency.
And for the same reason, a new 21-tooth escape wheel has been designed.
It is possible to find it with either 17 oche or 25 rubini.
Its charge reserve is 40 hours.