Fangrui Product Details 1. Gf-808 Wired Non-visual Single-family Intercom Doorbell 2. Functions: 3. Two-way Intercom And Unlock Function. 4. Two-core Wire Connection, Four-core Wire Connection With Unlock. 5. The Door Machine Is Surface-mounted Design And Easy To Install. 6. Using New Abs Plastic, Durable. 7. There Is An Excellent Side Tone Cancellation Circuit, And The Intercom Sound Is Clear. 8. Effective Intercom Distance Is More Than 100 Meters. 9. Easy Installation, Users Can Install It By Themselves. 10. Power Parameters: 11. Audio Undistortion Rate> = 50mw 12. Talk Time: Unlimited, Free Call 13. Power Adapter Input Voltage: Ac 220v 50hz 14. Power Adapter Output Voltage: Ac 12v 1200ma 15. Frequency Response: 300-3400hz +- 3db 16. Working Voltage: Dc 12v +- 17. Power Consumption: Static <0.2w, Call Status <2w 18. Installation: Hands-free Wall Mount 19. Indoor Extension Size: 227x87x45mm 20. Door Machine Size: 100x36x73mm