Thunderflash

Not exactly thunder and not much of a flash, but you get the idea. Used as a training replacement for grenades, and for the age old trick of firing tin helmets / bowls etc quite a good distance in to the air. For those that didn't know this one, it was publicised in an excellent training film called "The Stupidity Factor", an army video which contained a whole host of other great things to do on a wet afternoon on exercise.

Now sadly replaced by the slightly less butch sounding "Noise Generator"