This mini black ultrasonic dog repeller combines high-frequency ultrasonic waves and strong flashing LED lights to safely scare away aggressive stray dogs and train noisy pets without injury. Its compact matte black body is crafted from wear-resistant ABS plastic, lightweight enough to slip into pockets, handbags or keychains for all-day carry. Built-in rechargeable lithium battery supports Type-C fast charging, removing the trouble of frequent battery replacements. Adjustable ultrasonic modes work for small puppies and large fierce dogs, while the flash light boosts deterrent effects at night for jogging, walking and late commutes. Ergonomic one-button design enables simple operation for all users, equipped with low-battery reminder and auto power-off to save power. Built-in overcharge and over-discharge circuits ensure long service life. Ideal for couriers, pedestrians and outdoor lovers, this portable repeller provides reliable personal safety protection in residential roads, parks and alleyways, an essential outdoor safety gadget for daily trips.