More information about the movement from Worn and Wound:
They’ve rather made a new version, the 1.1, that has some intriguing features and slight changes to the case. First, Lemania 5100 movements aren’t available, so Sinn used their in-house modified Valjoux 7750, the SZ01, to get the same features. This isn’t just a look alike—it does have the essential central 60-minute counter. On Sinn’s version, the minute hand actually jumps at the end of the minute as well, which is a slight legibility improvement over the 5100.
From Hodinkee:
The movement powering the EZM 1.1 Mission Timer is the SZ01, which is a modified Valjoux 7750 that has a 60-minute stop function that sits on the watch’s central axis, allowing at-a-glance reading of the entire elapsed mission time—both minutes and seconds. the movement runs in 28 jewels, is anti-magnetic and shock resistant to DIN standards, and has a 42-hour power reserve.
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My comments: What makes the watch special is they reworked the valjoux 7750 into a central seconds chronograph to replace the discontinued Lemania 5100. It is more precise than the 5100 because as the second hand reaches 60 seconds the minute hand jumps to the next minute marker where the 5100, the minute hand would move continuously until at 60 seconds it would be pointing at the next minute. This watch is the first EXM with the reworked valjoux movement.