Winter poses numerous concerns on the watch wearer — functional, sartorial and from time to time complex inquiries. Like the ref. 6536 earlier mentioned, it had been obtainable in possibly chronometer and non-chronometer variants, but this was the first time the COSC watches essentially experienced the 'Formally Certified Chronometer' text https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/