In 2017 Swedish defense firm Saab got its second order for its AT4CSER one-shot shoulder fired rocket launchers. The CS stands for "Confined Spaces" and “ER” is for extended (600 meters) range. The first customer (in 2014) for the AT4CSER was France. The second customer is unnamed but delivery is set for 2018 and the mystery buyer will probably be revealed by then. Saab had hoped for more interest from the CSER model, as the CS model itself proved quite popular.
The AT4CS is considered a separate model of the AT4 that weighs about 10 percent more (and costs more as well) but is has become a best seller. The majority of AT4s sold to the United States are the CS model. The standard AT4 has to be used in the open because of the back blast. Thus in 2015 the when the United States delivered 2,000 AT4CS to the Iraqi military, that was the model the Iraqis preferred because most of their fighting was in urban areas and the CS model made more sense. Note that half of this 2015 shipment was held back for training purposes, since it does require some practice to become proficient with the AT4.
The AT4 was introduced in the mid-1980s and the first major customer was the United States. In fact, the U.S. ordered so many (for the army, marines and SOCOM) that most of the 350,000 AT4s used by the Americans were manufactured under license in the United States. The U.S. Marines have been using AT4 since the 1990s and Iraqis who saw it in action were impressed. The 6.8 kg (15 pound) weapon has a range of 300 meters and can destroy bunkers as well as armored vehicles. Many have been used in Iraq and Afghanistan by American and other NATO forces.
The AT4CS can be fired from inside a building and that capability attracted U.S. SOCOM (Special Operations Command) and the U.S. Marine Corps to buy many of these. The AT4CS is a one shot system that can operate with reusable night vision equipment. The standard 1.8 kg (four pound) 84mm rocket is fired from a one meter (40 inches) long launcher. The maximum range of the rocket is about two kilometers but effective (accurate) range is 300-400 meters for most rockets. The warhead doesn't arm until the rocket is about ten meters from the launcher. It takes about one second for the rocket to go 250 meters. The standard warhead can penetrate about 500mm (nearly 20 inches) of steel armor. Thus the AT4 is very useful against the thick walled compounds commonly found all over Iraq.
There are specialized rockets usable in the standard or CS models. These include HP (20 percent higher penetration of armor or masonry), HE (high explosive that can be set for air burst and thus have an effective range of 1,000 meters) and the ER (extended range).