Acme 535 Silent Dog Whistle

The Acme Silent dog whistle is a variable pitch whistle between 5200Hz to 12880Hz. and although insignificant to human hearing at its high frequencies is very effective to a dogs more sensitive ears and has a range of up to 2 miles (3 km).

The pitch is adjusted by screwing the whistle further in out and is secured with a brass grub-screw.

Comes complete with its own fully detailled instruction booklet