Clear Voice & Sound Adjustment: Big and adjustable speaker, clear voice, can be used as mobile interphone. Our loudspeaker has a powerful and user-friendly design, with adjustable sound cleaning, to take care of the elderly at home, without worrying about not hearing the ringtone or hearing the sound Dual-Way Intercom: Press the room to room intercom on outdoor-bell, indoor-bell will ring, now hold Answer Button on the indoor-bell to speak. 1 outdoor-bell can paired with 1 indoor-bells, the perfect combination allows you to communicate with visitors outside the door 5-50m Long Distance Wireless Range: Portable wireless voice intercom doorbell with long working distance, the maximum open distance can reach 5-50m. The two-way voice intercom doorbell is suitable to house, factory, hotel, hospital, super market and office. The intercom doorbell is protable and beautiful, convenient to use 4 Months Standby Time: The frequency of use of this wireless entry intercom is in accordance with national regulations and will not cause harmful electromagnetic interference, which is universal worldwide. Low power consumption, long standby time for outdoorbell up to 4 months