While the U.S. Army is investing hundreds of millions of dollars into developing a new generation of UAVs (Unmanned Aerial Vehicles), they are also spending money on upgrading existing ones. Recently, the new version of the Hunter UAV, the Hunter II (MQ-5B) made its first flight. The Hunter is actually an adaptation of an Israeli UAV, the Heron. The Hunter II is based on the latest version of the Heron (which is still used by Israel). The original Hunter is considered second best to the U.S. Air Force Predator UAV, but the Hunter II closes some of the performance gap. The Hunter II is a 1.5 ton aircraft with an internal payload (sensors, mostly) of 300 pounds, and an external payload (missiles or sensors) of 700 pounds. The Hunter II has an endurance of 29 hours (compared to 18 hours for the MQ-5A, which is actually an improvement over the original MQ-5A). The MQ-5B has better electronics and structural improvements. The "B" model is expected to be replaced by an entirely new design by the end of the decade.