There are two; take one or both.
Been laying around for years, never used. They're 20 inches long, roughly the size of a badminton racket. I've seen others in action, and they do work, once you've found your aim.
CAUTION: These are not toys! Keep away from kids! Anyone messing with these is in for quite a (literal) shock, since there's thousands of volts present when the button is pressed. Used properly they're quite safe; messed with, they're dangerous.