Time fuzes are useful for a variety of situations. For example, during World War 1 they were used to inflict an airburst effect upon enemy trenchworks and exposed units, shredding them from above regardless of cover. During World War 2, well-calculated time fuzes were essential for heavy anti-air batteries to create deadly "flak clouds". A less conventional use for time fuzes is as a backup self-destruction measure, as in the RPG-7s HEAT rockets, which self-destruct after 4.5 seconds if their impact fuze does not detonate.
