Military Style Watches

You'll want a watch that not only "takes a lickin' and keeps on ticking'," but one that can be easily field repaired, cleaned and parts replaced if necessary. These are the following characteristics you should be looking for when selecting your timepiece.

Construction

Large, lightweight, durable, non-reflective case.
Thick, rubberized strap or bracelet with a strong, secure clasp and preferably screweded to the lugs instead of the more common spring pins.
Large buttons that are easy to use with cold, gloved, and/or injured hands.
Tight, but easily rotating bezel.
Backup, solar powered, or field changeable batteries.

In addition to being able to keep accurate time, the following functions come in very handy in the field and are sometimes an absolute necessity.

Functionality

Water resistance to 100M is a minimum.
Multiple timers and alarms, preferably ones that can be silenced or at least set to vibrate.
Ability to operate in extreme climate conditions.
Thermometer/Temp reading
Easily readable display.
Blackout or inverse LCD, or Tritium type dials for reading in low-light conditions.
Depth meter, Altimeter, Barometric monitoring and an electronic or standard compass.
GPS
Easy to use, easy to access/update software for uploading data to/from your PC.

Make sure you are familiar with your watch's functions BEFORE taking it to the field and relying on it. And remember that many of the above functions like GPS, Barometric monitoring, etc. eat up your battery life so make sure you have a contingency for this.