Unlike the very similar IWC and Patek Phillipe an Eterna calibre 520 is a relatively affordable watch. The beautifully scaled down pocket watch design is satisfyingly aesthetic with its hidden ratchet and crown wheels under highly finished bridges. The calibre 520 had several upgraded during its run including several shock protections upgrades and a sweep seconds variant. The Germans ordered 520 powered watches for their airforce and the British had WWW Eterna 520 officers watches.
