The device emits sound waves. To use it effectively, please note the following: Features of the dog and cat repeller: - Used to repel dogs, cats, monkeys, and other animals. - Helps train your dog to reduce barking and improve obedience. - Trains your dog to reduce unwanted behaviors such as jumping, digging, and scratching. - Also trains your dog to sit, stand, and perform nighttime security patrols, among other positive behaviors. - Lightweight and easy to carry and use. - Comes with a wrist strap for more convenient use. - Operates in two modes: training mode and repelling mode. Charging: - The sound will disturb the dog but will not harm it. - Not effective on deaf dogs. - Recommended for dogs over 6 months of age. - Emits a 25 kHz sound wave, which falls within the dog's hearing range of 15 Hz to 120 kHz. - Has no effect on humans and cannot be heard by them at all, because the human hearing range is between 20 Hz and 20 kHz, making it completely safe. - Can be used to repel stray dogs while running, walking, cycling, waiting in a park, in a car, or similar situations. - The device includes two built-in LED flashlights and operates on a 9V rechargeable battery, providing ultra-bright illumination in the evening. - Compact and suitable for carrying in your pocket, ready for use anytime. - Suitable for indoor and outdoor use. - Delivers real results with sound waves that will scare dogs when they hear them. - Rechargeable. Functions in brief: 1. LED flashlight. 2. Trainer for personal and security dogs. 3. Repeller for stray animals. Specifications of the dog repeller device: - Color: Black. - Material: ABS + electronic components. - Dimensions: 14.91 × 7.9 × 3.61 cm. - Weight: 132 g. - Frequency: 25 kHz. - Battery: Rechargeable. Price: 150 (includes free shipping via SMSA)