A powerful weapon in John Brunner's non-novel Stand on Zanzibar. The kazow is a miniature pistol-sized rocket launcher, firing small homing projectiles which can be outfitted with a nuclear payload in addition to standard explosives.
Each rocket contains a tiny (but highly advanced) guidance system which can be set by a knob or dial attached to the kazow. The rockets are able to seek out several types of targets through heat detection: humans, refrigerated tanks, or metal surrounded by vegetation.
The kazow is standard issue for United States marines (especially useful for missions where the enemy resides in a fortified position,) but it is difficult for civilians to obtain one due to futurisic gun control legislation (in the year 2010, there is no NRA.)