The M1 Abrams or Abrams Main battle tank is a military tank produced in the United States. The Abrams entered service in the U.S. during 1980, replacing the M60 Patton and M48A5. The Abrams features a well armed, heavily armored and highly mobile offensive armored ground warfare. Other features include the use of powerful gas turbine engine, a sophisticated composite armor and separate ammunition storage in a blow-out compartment for crew safety. The Abrams was designed by Chrysler Defense. An improved version of the M1 was the M1A1, which was introduced in 1985. While the M1A2 was a further improvement of the M1A1 with a commander's independent thermal viewer and weapon station, position navigation equipment, digital data bus and a radio interface unit. During World War II, an average of 17 rounds took a Sherman Tank to destroy an enemy tank 700 meters way. Though Abrams remained untested in combat until the Gulf War in 1991, a total of 1,848 M1A1s were deployed in Saudi Arabia.