A conventional explosive item designed to be dropped from an aircraft and destroy deeply buried targets. it is designed for a specific function, such as the destruction of bunkers and tunnels in a particular type of terrain. this item may be guided. it does not have a power source to increase its speed. for bombs that achieve penetration by acceleration, see bomb, penetrating. for penetrating bombs that do not have a means of acceleration and can be set to explode above or below ground, see bomb, general purpose.