Synchronous Multilayer Bomb

A Synchronous Multilayer Bomb is a type of tactical weapon created in Academy City.

Background
It is a large bomb that has high power explosives arranged in a regulated manner. A normal tactical weapon spreads an enormous blast over a large area while the synchronous multilayer bomb was made to focus a highly destructive blast on one small target so as to utterly destroy it. It was created in order to bomb an enemy stronghold in an urban environment with no civilian sacrifices.

Battle Royale Arc
BLOCK wanted to set off one of these bombs inside the Windowless Building in an attempt to kill Aleister Crowley. They planned this in an attempt to stop the chaos in the world from turning into a war. As the Windowless Building was impervious to even a nuclear attack they wanted to discover the route through which materials are brought into the windowless building. To do this they attacked the Reformatory in an attempt to take the Move Point's companions hostage and use them as leverage to find her identity. Once this was done they planned to negotiate with her to find the route they needed. In the end, however, GROUP was able to defeat BLOCK and stop their plans.