The AT4CS AST is an anti-structure tandem weapon that has special internal ballistics allowing it to be fired from confined spaces; tight jungle, in front of obstacles, or even with its own troops in close vicinity. Using the AT-4CS AST the dismounted soldier has a unique weapon to effectively take advantage of the building structures of the urban battlefield and at the same time deny the enemy that same advantage. The AT4 is a Swedish 84 mm (3.31 in) unguided, man-portable, single-shot, disposable, recoilless smoothbore anti-tank weapon built by Saab Bofors Dynamics (previously Bofors Anti-Armour Systems and before that FFV Ordnance). While the Carl-Gustaf is the reusable weapon in the Saab portfolio, the AT4 is the disposable one, the two systems share the same caliber, 84 mm, which means that ammunition warheads can be used for both systems. Saab has had considerable sales success with the AT4, making it one of the most common light anti-tank weapons in the world.
The AT4CS AST is based on the same manufacture as the basic model AT-4, only the ammunition used changes. AT4CS AST combines the firepower of the tandem warhead with the ability to fire from confined spaces and other narrow firing positions. Where conventional shoulder-launched weapons would force the gunner to leave cover for a more open and exposed firing position, the unique internal ballistic design of the AT4CS AST systems allows maximum use of the protection offered by the urban environment. The AT4CS AST is optimized to defeat a multitude of targets characterizing the urban environment ranging from building structures to light armored vehicles. The launch tube includes a forward grip, flip-up sights with an adjustable rear sight, and a trigger button. The tandem warhead of AT-4CS AST is designed to be able to defeat a large number of different targets, ranging from an enemy position behind heavy brick or reinforced concrete walls to an enemy within a field fortification or in a light armored vehicle.