ZENITH Solidifies its international popularity since the foremost manufacturer of precision chronometers and devices across many domains. Meanwhile, Graham has also ventured beyond their comfort and ease zone with a few bigger echelon parts. Their Orrery Tourbillon, a constrained edition of 8 pieces, possesses a 100 12 months calendar complication, https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/