707mm2
·On Tony‘s sold example there isnt any evidence on the movement that the watch was certified as chronometer right?
On most Longines chronometers, there's no indication written directly on the movement, only on the dial or a certificate if you're (extremely) lucky. Only a few models had mention of their adjustments (like the Ultrachron). Especially for the 34x and 29x families there's no way to distinguish by eye if the movement is an actual chronometer, only an extract from Longines' archives can help.