CBU - 100 Cluster Bomb The CBU - 100 Cluster Bomb ( also called the Mk - 20 Rockeye II ) is an American cluster bomb which is employed primarily in an anti - tank mode . It weighs 490 pounds and carries 247 " Mk 118 Mod 1 bomblets " . The anti - tank cluster bomb is an air - launched , conventional free - fall weapon . The Mk 20 , CBU - 99 , and CBU - 100 are used against armored vehicles . Design . When the Mk 20 bomb cluster is released from the aircraft , the arming wires ( primary and / or optional arming ) are pulled sufficiently to arm the Mk 339 fuse ( and recently the FMU - 140 fuse ) and release the fins . The positive armed fin release arming wire frees the fin release band , and the movable fins snap open by spring - force . Functioning of the fuse initiates the linear shaped - charges in the dispenser that cut the dispenser case in half and disperse the bombs / bomblets . When the Mk 339 Mod 1 primary fuse arming wire is pulled , the fuse will function 1 . 2 seconds after the arming wire has been extracted . If the pilot selects the option time ( 4 . 0 seconds ) , both the primary and option arming wires must be pulled . If the pilot selects the option time and the primary arming wire is not pulled , the fuse will be a dud . Deployments . The CBUs are delivered to the fleet as completely assembled all - up - rounds ( AURs ) . Fuzes , suspension lugs , arming wires , wire extractors , and all other necessary components are installed . The information on configuration , functional description , and shipping and storage containers of the Mk 7 bomb dispenser and its associated components can be found in NAVAIR 11 - 5A - 3 , also information on decanning , preparation for use , and recanning procedures are found in NAVAIR 11 - 140 - 9 . MK 20 MODS / CBU - 99 / CBU - 100 , BOMB CLUSTER CONFIGURATIONS The configurations of the Mk 20 Mods / CBU - 99 / CBU - 100 are listed in the table below . Mk 7 and Mods Bomb Dispenser The cargo section of the Mk 7 bomb dispenser is the main structure of the weapon and contains the bombs / bomblets . A nose fairing is attached to the forward end of the cargo section for aerodynamics and fuze installation . It has an observation window for viewing the safe / arm indicator on the installed fuze . The dispenser has two linear - shaped charges secured longitudinally inside the walls . When initiated , these shaped charges cut the dispenser in half , from front to rear , and the bombs / bomblets spread in free - fall trajectories . To stabilize the weapon after release from the aircraft , a tail cone assembly is attached to the aft end of the cargo section . The tail cone assembly houses four , spring - actuated folding fins . The fins are spring - loaded to the open position and secured in the closed position during ground handling by a fin release - band assembly . The fin release band is secured in the closed position by a safety cotter pin and by the fin release wire . A yellow band around the forward end of the cargo section indicates the explosive content of the weapon . The Mk 7 Mods 3 , 4 , and 6 bomb dispensers have the Mk 339 Mod 1 fuze , which provides the pilot with in - flight selection of the fuze function time . The Mk 7 Mod 4 bomb dispenser differs from the Mk 7 Mod 3 by modifying the dispenser and giving interface capabilities with a wider range of military aircraft . The Mk 7Mod 6 bomb dispenser is the same as the Mk 7 Mod 3 except that the outside of the Mod 6 cargo section is coated with a thermal protective coating and has an additional yellow band around the forward end of the cargo section . The addition of the thermal coating increases the overall weight of the Mod 6 to 505 pounds Each bomblet weighs and has a shaped - charge warhead of high explosives , which produces up to 250 , 000 psi ( 1 . 7 GPa ) at the point of impact , allowing penetration of approximately of armor . Rockeye is most efficiently used against area targets requiring penetration to kill . Fielded in 1968 , the Rockeye dispenser is also used in the Gator air - delivered mine system . During Desert Storm US Marines used the weapon extensively , dropping 15 , 828 of the 27 , 987 total Rockeyes against armor , artillery , and personnel targets . The remainder were dropped by Air Force ( 5 , 346 ) and Navy ( 6 , 813 ) aircraft . According to a test report conducted by the United States Navy ' s Weapon System Explosives Safety Review Board ( WSESRB ) established in the wake of the tragic 1967 USS Forrestal fire , the cooking off time for a Rockeye CBU is approximately 1 minute 13 seconds .