Features 1、3 ADJUSTABLE LEVELS: Bark control device has 3 levels of sensitivity (effective range at 4.5, 9 to 15.24 m) and a test level. There are 3 frequency levels (15‑30 KHz, suitable for large, playful dogs; 20KHz for gentle dogs; 30KHz suitable for small dogs). 2、USB RECHARGEABLE: Anti barking device requires no battery installation and can be used for up to 30 days on a 5 hour charge with a power indicator that can be set to "Off" to defend the battery when you are away. 3、AUTOMATIC: When excessive barking is detected, the dog bark deterrent will sense the barking and activate the component, which effectively stops the dog from barking and does not require a receiving collar. Sensor distance up to 33 feet. 4、ULTRASONIC: Dog barking control devices emit a safe, high pitched beeping sound wave that can be heard by dogs but not by humans. The dog is stimulated by the sound and will stop barking. Suitable for all breeds and sizes of dogs. 5、PORTABLE: Ultrasonic barking deterrent is designed to look like an alarm clock, it can be hung from a tree, anywhere in the house or in your yard, it can be hung, placed on a table or anywhere else. Specifications: Item Type: Bark Control Device Material: ABS Battery Type: Lithium Battery ( Shipped with Built in Battery) Battery Capacity: 1500mAh Waterproof IP Rating: IPX4 Ultrasonic Frequency: 15‑30KHZ Sensor Distance: Up to 33 Feet Size: Approx. 11x8.5x3.7cm / 4.3x3.3x1.5in Package List 1 x Bark Control Device 1 x USB Charging Cable 1 x English Manual 2 x Screws 2 x Expansion Tube