The bomb is reportedly four times as powerful as the US military's GBU-43/B Massive Ordnance Air Blast bomb (whose official military acronym "MOAB" is often colloquially called the "Mother of All Bombs"). This Russian device would therefore be the most powerful conventional (non-nuclear) weapon in the world. The veracity of Russia's claims concerning the weapon's size and power have been questioned by US defense analysts. "FOAB" was successfully field-tested in the late evening of September 11, 2007. The new weapon is to replace several smaller types of nuclear bombs in its arsenal.