GBU-39 Small Diameter Bomb
The GBU-39 Small Diameter Bomb (SDB) has the same guidance and ballistics of larger bombs equipped with the latest Joint Direct Attack Munition guidance strap-on kit, but offers other advantages. Especially with new explosives, it is exceptionally destructive to a small area, but produces much less damage outside that area. Its lower weight also provides greater range for the same number of bombs, considered especially important by the Israelis. 
Three GBU-39s nominally fit into a single mounting position for a Mk. 84 2000 pound bomb, but can be launched separately, in a Triple Ejector Rack on wings or in a rotary launcher.
Initially, they contained either a conventional explosive filler, or, for some precision targets, inert concrete so they did damage only by kinetic energy. The U.S. Focused Lethality Munition program, is developing GBU-39's filled with dense inert metal explosive to decrease the blast radius while increasing lethality within it.