The KC-135 anti-collision strobe lights are high-density, dual-color strobes mounted on the top and bottom of the fuselage, flashing at 45–60 flashes per minute. Each strobe is powered by a separate 28 Vdc power supply. The upper strobe’s power supply is located inside the fuselage below the light, mounted on the side of the air conditioning duct. The lower strobe’s power supply is located in the keel beam on standard tankers or mounted on the side of an upper fuselage air conditioning duct for remaining aircraft.