The T-54 and T-55 combines a high-velocity gun with a highly mobile chassis, low silhouette, and exceptional long-range endurance. The T-54/55 tanks have been produced in greater quantity than any other tank in the world. Seven main production models have been widely used throughout the Warsaw Pact and in many other countries. The T-54/55 series has been manufactured in Czechoslovakia and Poland as well as in China where it is known as Type 59. More than a dozen countries have produced upgraded T-55 variants with similar capabilities in protection and lethality. The tank featured many innovations, many of these being in the fire controls of the T-54 and the T-55.