ULTRASONIC FUNCTION - Based on the theory that the dog trainer can effectively train your dogs to be obedient and discourage unwanted behaviors like barking, digging, chewing and more. Also, they are harmless to both humans and pets EASY TO USE - Open the battery cover first, then insert a 9V battery. The sound is only audible for pets. Finally, turn on the switch and it can work well. If necessary, it can also be used as a flashlight. LED FLASHLIGHT BATTERY INDICATOR - Super bright LED flashlight function is helpful when walking or jogging at night, which also works as a battery indicator. HAND-FRIENDLY CONVENIENCE - This device can be used anywhere - The size of the device is Size: 13 x 5 x 2.5 cm/5.12"" x 1.96'' x 0.98""; Wrist Rope: 18cm/7.08''; Weight: 0.14kg/4.93oz; Package Include: 1 x Handheld Dog Repellent Portable and handy, also convenient to take with you, e.g. such as jogging or walking, cycling, parking, etc. MULTI-FUNCTION - Except as a pet training tool, it can also protect you from dog attack. It is suitable for training many types of dogs, e.g. B. Pets, dogs in police and shepherds, suitable for outdoor work, travel and security night patrol."