A Nivarox Branded Observatory Competition Peseux 260 From the 1950s
Today Nivarox operates largely behind the scenes, supplying the beating heart inside the vast majority of spring-powered Swiss timepieces, from Swatch to Patek Philippe. The low escape wheel in this caliber allowed for a larger balance wheel & thus better rate stability. Kari Voutilainen later employed the Peseux 260 in his series of Observatoire timepieces, which were awarded certificates of chronometry from Besançon Observatory.
Image from ebay listing