Accoring to wikipedia: "A large number of General Dynamics F-16 Fighting Falcon variants have been produced by General Dynamics, Lockheed Martin, and various licensed manufacturers. The details of the F-16 variants, along with major modification programs and derivative designs significantly influenced by the F-16, are described below.
...This variant, which is also known as the Block 50/52+. Its main differences are the addition of support for conformal fuel tanks (CFTs), a dorsal spine compartment, the APG-68(V9) radar, an On-Board Oxygen Generation (OBOGS) system and a JHMCS helmet.
The CFTs are mounted above the wing, on both sides of the fuselage and are easily removable. They provide an additional 440 US gallons or approximately 3,000 pounds (1,400 kg) of additional fuel, allowing increased range or time on station and frees up hardpoints for weapons instead of underwing fuel tanks. All two-seat "Plus" aircraft have the enlarged avionics dorsal spine compartment which is located behind the cockpit and extends to the tail. It adds 30 cu ft (850 L) to the airframe for more avionics with only small increases in weight and drag."