Patek Philippe's celebrated reference 3969 series was made in a limited edition of 450 examples in pink gold and 50 in platinum to celebrate the company's 150th Anniversary in 1989. The model is a reproduction of the jump hour watch originally launched by Patek Philippe in the 1920s.
The particularity of a jump hour watch lies in its unusual mechanism and appearance. The hours are indicated by a small disc turning underneath a window. The disc rotates every time the minute hand, set within the centre of the dial, hits the full hour. The tonneau-shaped case was a typical design of the 1920s and is currently reliving a nostalgic popularity.

Both jump hour models are described and illustrated Patek Philippe Wristwatches by Martin Huber & Alan Banbery, second edition, pp. 120 & 121.