It is a fully tracked vehicle capable of limited amphibious operation in lakes and streams, extended cross-country travel over rough terrain, and high speed operation on improved roads. The M113 family has many variants and modifications that are used in a variety of combat and combat support roles. Approximately 80,000 units of all types have been produced worldwide making it one of the most widely used armored fighting vehicle of all time. Although not a tank, or even designed as a fighting vehicle, the M113 was the most utilized armored vehicle of the Vietnam War. It inspired newer generations of more heavily armored and armed infantry fighting vehicles. Yet it remains in front-line service and production in the 21st century, and the M113 was recently declared the best in a television comparison of 'top 10' armored personnel carriers and infantry fighting vehicles.