Enhanced Security & Convenience: This wireless doorbell operates on a 433MHz frequency, offering reliable and secure communication. With a range of up to 250 meters Built-in dual speakers: Ideal for use in homes, offices, factories, and stores. The dual speakers ensure clear sound, making it perfect for welcoming guests or enhancing security Customizable Alerts: Choose from 36 different ringtones to personalize your doorbell chime. Adjust the volume with three levels - high, medium, and low - using the dedicated volume control button on the receiver Eco-Friendly Design: Built with a commitment to environmental safety, this doorbell is mercury, lead, and UV-free, ensuring zero pollution and contributing to a greener planet Easy Installation: The transmitter should be mounted at a height of approximately 1.5 meters for optimal performance. Simply plug the receiver into a power outlet to get started. No complicated wiring or setup required Specifications: Material: ABS Working distance: up to 250 meters Receiver size: 75*45*25mm Transmitter size: 76*45*25mm Receiver working voltage: 110-240V Transmitter working voltage: 12V 23A battery * 2 (included) Receiver buttons: 1) Music: 36 ringtones are optional, and the music logo button on the side is used for adjustment 2) Volume: Three-level volume adjustment (high, medium, low), and the volume logo button on the side is used for adjustment 3) Can be set to sound and silent (sound: sound + indicator light Silent: indicator light)