Over the last four years, the U.S. Department of Defense has equipped nearly 40,000 hummers with the VEE emergency exit windows, at a cost of about $3,700 per vehicle. The new window takes about an hour to install, and replaces the existing bulletproof window with one that has a latch system. It takes about five seconds to turn the latches and push the window forward. This enables troops to get out of vehicles that have rolled over, or gone into the water, and jammed the doors. For vehicle that have caught fire, either from an accident or roadside bomb, the VEE has proved to be a lifesaver. The VEE window has since been adapted for use on other types of armored vehicles.