The dog whistle has adjustable pitch for active control of the frequency produced. When you blow on the whistle?? you can hear the secondary sound made by the air forced through the metal tubing.

Descript"n:

• Condition: Brand new
• Color: Silver
• Material: Nickel Plated Brass
• Length: 2 1/8 inch
• Key ring loop included
• Adjustable pitch?? simply tighten or loosen the screw to work out your dogs frequency
• It should be noted that this whistle is audible to the human ear?? essential for gauging its efficiency.