Personal Cloaking Field
The cloaking device is an immensely useful device, that must be held in one hand, but enables you to get much closer to aliens without them being able to see you. However, it works for the aliens as well, and although it is fairly easy to defeat (smoke grenades, rush up, kill), occasionally you may find an alien with a cloaking device and an entropy missile launcher, which is a deadly combination. But overall it is very useful. However, be sure to remember that it does not make you invisible, just harder to see, so suicide attacks with a cloaking device and Power Sword will result in a dead soldier and nothing else.
Official Entry: "The Personal Cloaking Field generates a warping effect that bends various wave forms. Effectively this means that the user is considerably less visible to radar, infra-red and visual sighting. The field is disabled temporarily if the user initiates combat."