What is the 'mother of all bombs' which US might use against Iran?

The GBU-43/B Massive Ordnance Air Blast Bomb, nicknamed "mother of all bombs", is the largest non-nuclear bomb in US arsenal that it might use against Iran. Containing about 8,500 kg of high explosives, it explodes shortly before hitting ground, sending devastating blasts that can cause widespread destruction. It's typically deployed from Lockheed C-130 Hercules cargo aircraft because of its size.