Features:1. Fire-new and high quality， with great waterproof performance2. 36 kinds of melodies for option3. You can install the doorbells in locations， such as kitchen， back yard， bedroom， etc. never miss the guest4. Complete wireless operation - no wires or cables required5. Energy saving design of environment protection6. With double-sided sticker at the back side of the remote button， very easy to install7. Ultra-distance represents the technology of surpassing obstacles8. Keep you aware of intruders or visitors anywhere around your home9. No battery included Specifications:1. Material: ABS2. Melodies: 36 Kinds3. Remote Distance: 100m4. Sound: 25-80dB ( 4-grade Volumes)5. Working Frequency: 315MHz6. Power Plug: US Plug7. Working Electricity of the Emitter�Q15mA8. Temperature: -10 �� ~50 �� 9. Wireless Doorbell: Yes10. Application Range: Apartment， Service Flat， Hotel， Office， Business etc.11. Dimensions: (3.74 x 2.36 x 1.34)" / (9.5 x 6 x 3.4)cm (L x W x H)12. Color: Black13. Weight: 3.84oz / 109g Package Includes:1 x Emitter1 x Receiver1 x Double-sided Sticker1 x User Manual