The Hamilton 623 is a mechanical watch movement featuring an automatic function, sweep second hand, day and date display, and a jeweled lever. Manufactured around 1975, this movement sets the day by +/-24 hours and quicksets the date by reverse setting. Notably, in late samples, the hairspring terminal is glued, the stem mechanism does not include a setting-lever spring, and the train and hand gear are strangely driven separately by the barrel.