My dad had one of these when he was a kid. It was a cap bomb, a toy for kids in the 50's. I don't think kids nowadays would have any fun with this. The cap grenade is shaped like a bomb or missile from said time period, and has a rotating top, allowing a cap to be placed within. The toy would then be thrown, exploding the cap upon impact and making the sound effect. SHARE if you remember!! and if you love the good old days....