Health Droids (or FX-7s) are medical droids sprinkled throughout some star wars games that look like a blue cylinder with little arms sticking out of them. They are almost always accompanied by nearby ammo droids. In the battlefront series when you get close enough to one, your unit will flash blue, and your health will slowly be replenished. They are very handy in combat and you will always find yourself looking for one, no matter how good you are.