The Thunderer whistle from Acme is made from solid brass and is a pea whistle with a high pitch. It is small-sized and has a tapered mouthpiece.

The medium Thunderer whistle from Acme is made of solid brass, is a pea whistle, has high power and medium pitch 114dBA. It is medium-sized with a tapered mouthpiece.

The Large Thunderer whistle from Acme is made from solid brass and is a pea whistle with a high pitch. It is small-sized and has a tapered mouthpiece.