The specifications

The EZM-1 provides many interesting features that make this watch unique :

• Titanium case
• Shock proof
• Antimagnetic
• 30 BAR (300m water resistance)
• Argon filled
• Chronograph
• Date
  
• Light weight (61g without the bracelet)
  
• Lemania 5100 movement
• left sided crown and pushers.

The use of titanium ensure a great resistance to shock and provides a limited weight for the watch. The Lemania 5100 is an automatic movement that is no longer produced. that's why Sinn stopped the production of EZM-1. However, because they had spare movements in reserve, Sinn decided to use them and launched the Limited edition of 250 EZM-1 watches.
You can also find the Lemania 5100 in other watches and brand (in some Omega speedmaster, Sinn 156, Sinn 142 Ti Ar, Tutima, Orfina, Alain Silberstein. . .).

The fact that the pusher are on the left side of the watch (instead of the right on most of the watches) is intentional : pusher will not interfere with normal moves of the wrist and  when bending during exertion, including rappelling, and shooting. 

All those features make the EZM-1 a perfect tool watch!