GBU - 28 The Guided Bomb Unit 28 ( GBU - 28 ) is a 5 , 000 - pound ( 2 , 268 kg ) laser - guided " bunker busting " bomb nicknamed " Deep Throat " produced originally by the Watervliet Arsenal , Watervliet , New York . It was designed , manufactured , and deployed in less than three weeks due to an urgent need during Operation Desert Storm to penetrate hardened Iraqi command centers located deep underground . Only two of the weapons were dropped in Desert Storm , both by F - 111Fs . The Enhanced GBU - 28 augments the laser - guidance with Inertial navigation and GPS guidance systems . Design and development . In August 1990 , the U . S . military began planning an air offensive campaign against Iraq . Planners noticed that a few command and control bunkers in Baghdad were located deep underground to withstand heavy fire . Doubts were raised about the ability of the BLU - 109 / B to penetrate such fortified structures , so the USAF Air Armament Division at Eglin AFB , Florida , was asked to create a weapon that could , and engineer Al Weimorts sketched improved BLU - 109 variants . By January 1991 , as the Gulf War was well underway , it was determined that the BLU - 109 / B - equipped laser - guided bomb s ( LGB ) would be unable to penetrate fortified bunkers deep underground . The initial batch of GBU - 28s was built from modified 8 inch / 203 mm artillery barrels ( principally from deactivated M110 howitzer s ) , but later examples are purpose - built with the BLU - 113 bomb body made by National Forge of Irvine , Pennsylvania . They weigh 4 , 700 pounds ( 2132 kg ) and contain 630 pounds ( 286 kg ) of high explosive . The operator illuminates a target with a laser designator and the munition guides itself to the spot of laser light reflected from the target . The bomb underwent testing at the Tonopah Test Range , Nevada , a test facility for United States Department of Energy funded weapon programs . It proved capable of penetrating over 30 meters ( 100 ft ) of earth or 6 meters ( 20 ft ) of solid concrete ; this was demonstrated when a test bomb , bolted to a rocket sled , smashed through 22 ft ( 6 . 7 m ) of reinforced concrete and still retained enough kinetic energy to travel a mile downrange . The GBU - 28 is unique in that the total development time from conception to the first drop test took only two weeks , and the weapon went into active service after only one test drop , at Eglin AFB , Florida on 19 February 1991 . Operational history . On the night of 27 / 28 February 1991 , within hours of the ceasefire , two General Dynamics F - 111Fs , loaded with one GBU - 28 each , headed towards a target on the outskirts of Baghdad . The al - Taji Airbase , located 15 mi ( 27 . 4 km ) northwest of the Iraqi capital , had been hit at least three times by GBU - 27 / Bs from F - 117 Nighthawks , " digging up the rose garden " . The first GBU - 28 was dropped off - target due to target misidentification . The second GBU - 28 was a direct hit and penetrated the thick reinforced concrete before detonating , killing everyone inside . The bomb was used during Operations Enduring Freedom in 2002 and Iraqi Freedom in 2003 by USAF F - 15Es . The first foreign sale of the GBU - 28 was the acquisition of 100 units by Israel , authorized in April 2005 . Delivery of the weapons was accelerated at the request of Israel in July 2006 . Delivery was described as " upcoming " in a cable dated November 2009 which suggested that the weapon could be used against Iran ' s nuclear facilities . Fifty - five GBU - 28 ' s were delivered to Israel in 2009 . In June 2009 United States agreed to sell the GBU - 28s to South Korea , following the nuclear test conducted on 25 May 2009 by North Korea . The bombs will be delivered between 2010 and 2014 . According to the " Jerusalem Post " on December 23 , 2011 the US Justice Department announced that it had reached a settlement with Kaman Corp . which allegedly substituted a fuse in four lots of fuses made for the bombs . Under the settlement , Kaman Corp . will pay the government $ 4 . 75 million . Israel is concerned it had also received GBU - 28 bombs fused to prematurely detonate before penetration or at other times .