Pretty sure that’s one of the couple dozen USAF KC-135s modified under the Multi-Point Refueling System program to add underwing refueling pods.
There are primarily two types of aerial refueling systems used by military forces around the world. The USAF, and a small number of other military forces, use what’s called the “flying boom.” With this system a crewmember in the tanker a/c steers (“flies”) a refueling nozzle into the receiving aircraft. In the photo above ... Read even more
