iRobot may be best known for its household automatons, but the company's expertise goes far beyond circular bots built for sweeping and scrubbing floors. Its Warrior and 110 FirstLook bots are built for the military, and now the Advanced Inflatable Robot (AIR) arm model is joining its armed forces brethren. The AIRarm prototype is essentially a Packbot whose metal arm's been replaced with an inflatable version able to lift four times its own half-pound weight. That might not seem like much, but considering most rigid robot arms can only lift a fraction of their own weight, it represents a sizable gain in strength-to-weight ratio. Plus, the arm can get stronger by simply dialing up the air pressure. As an inflatable limb, it can also operate delicately around meatbags -- just as the air pressure is increased for strength, it can be decreased when in close proximity to people so as not to injure them. For its prototype effort, iRobot's going to get a $625,000 contract from DARPA to continue the AIRarm's development, and you can see a bit of what that money will buy in the video after the break.