Offered here is a rare Longines chronograph, circa 1960-1970s, powered by their Cal. 13ZN predecessor – the 30CH. This example, the Reference 7413, is fitted in a large, steel case, and features a screwback waterproof layout, and pump pusher chronograph buttons. This Longines chronograph is in good vintage condition. The case has been previously polished, but the lugs are thick and even, and the polishing was done lightly. The sunburst dial is in great condition, with no real wear/flaws.