a type of armored combat vehicle, tracklaying or wheeled with increased cross-country capability, designed to transport motorized infantry and various military cargoes and weapons. Armored personnel carriers are also used as command or staff vehicles, for communications and security, and for performing other special missions. The first models were developed in England in 1918. During World War II the warring armies were equipped with full-track, half-track, and wheeled armored personnel carriers with open hulls. Half-track armored personnel carriers have not been produced since the war. Today armored personnel carriers are capable of coordinated battle action with tanks. They can have a sealed, armored hull equipped with filter-ventilation devices for protection against radiation contamination and bacteriological and chemical weapons. They may also have day- and night-vision instruments and bulletproof armor. There are armored personnel carriers without turrets that have machine guns with a caliber of 7.62-12.7 mm and others which have a turret equipped with a 20-mm cannon and machine guns to wage battle or provide fire support for the combat action of an assault party unloaded from the carrier. The capacity of the armored personnel carrier is figured for a motorized rifle squad and usually does not exceed 13 persons. There are air-transportable and amphibious armored personnel carriers. Screw propellers on ships, water jets, or regular tracks are used as propelling devices on water. The maximum speed of full-track armored personnel carriers on terrain is up to 70 km/hr; wheeled carriers may reach 90-100 km/hr.