Our 3rd party tested and safety checked dog whistle with 49cm lanyard and lid with adjustable frequency and frequency lock. Stops barking and teaches recalls and tricks . No problem asking a dog whistle to stop barking, teach recall and tricks: yes, we developed a better dog whistle to stop barking and help train your dog. More frequency means better results for any dog of any age Adjustable frequency + frequency lock: Yes, our dog whistle has more frequency. Proprietary precision grinding produces a finer frequency range, which is why Simply Natural includes frequency locking so you'll never lose your dog's perfect pitch. Choose a Better Eco-Friendly Dog Whistle: Yes, we care about quality and the environment. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.