Here is more on the German SD 2 “Butterfly Bomb”, first dropped on Ipswich, England in 1940, and thereafter on both the eastern and western fronts. In the single month of August, 1943, a total of 520,000 were dropped, with the number limited by the supply available. Many SD 2s failed to explode or were deliberately fuzed as booby traps. Some of these long outlasted the war, with the most recent having been discovered (and safely detonated) in Malta in October 2009.
The butterfly bomb was the first example of a cluster munition, which became widely used in various forms around the world. They were banned by the 2008 Convention on Cluster Munitions, which has now been adopted by 123 states. Among non-signatories are China, India, Iran, Israel, Pakistan, Russia, the Turkey, and the United States. On 2023-07-06 U.S. president Joe Biden approved supplying cluster munitions to Ukraine for use attacking Russian troops occupying that country and/or for lucrative resale in the international arms bazaar.