1.QUALITY: Ultrasonic dog whistle. Stainless steel. High-quality materials are used to create dog-whistles that are built to last Efficient training and higher levels of obedience are now possible 2.Method of use: Loosen the sonic adjusting screw, blow the air in from the air inlet, and rotate the adjusting lever to adjust to the best pitch. After the adjusting rod is screwed, tighten the sonic adjusting screw. 3.ADJUSTABLE: Fully adjustable, you are able to select the frequency that works the best for your situation. This is important, as many cheaper dog whistles are not adjustable 4.ULTRASONIC: Our ultrasonic whistle allows you to fine-tune the pitch and just like the original whistle (or silent whistle) can not be heard by most humans. 5.PORTABLE and PROTECTED: Easy to take with you and our fully-adjustable dog whistle comes with a protective cover. We also include s a quality lanyard with a quick-release feature that allows you to remove the whistle from the strap quickly and easily.