"Father of all bombs" is the nickname of a Russian-made air-delivered thermobaric weapon that is claimed to be four times more powerful than the U.S. military's GBU-43/B Massive Ordnance Air Blast bomb (MOAB or the "mother of all bombs"), making it the most powerful publicly-known conventional (non-nuclear) weapon in the world. It was successfully field-tested in the late evening of September 11, 2007, when it was dropped from a Tupolev Tu-160 heavy bomber with a parachute and exploded.
The weapon yields the equivalent of 44 tons of TNT using 7.8 tons of a new type of high explosive, created applying nanotechnology. In comparison, the MOAB produces the equivalent of 11 tons of TNT from 8 tons of high explosive. The blast radius of 300 m is twice as large as the MOAB.
Although its effect has been compared to that of a nuclear weapon, it is comparable only to the lowest yield settings of the lowest yield nuclear weapons. The M-388 Davy Crockett, one of the smallest nuclear devices deployed, had a selectable yield between 10-20 tons of TNT (smaller than the FOAB) to up to 500 tons of TNT (over ten times larger than the FOAB). The FOAB only has around 0.3 percent of the power of the atomic bomb used against Hiroshima (a yield of 13 kilotons of TNT), which itself is considerably smaller than most modern nuclear weapons (which are usually measured in the hundreds of kilotons range, upwards into the megaton range).