Wireless Calling: This intercom doorbell is wireless, making it easy to use. It's great for the elderly or those with mobility issues who may need to call family members or caregivers at any time, from anywhere2 Way Voice Communication: The caller and receiver can engage in 2 way voice communication, ensuring smooth and conversations. The distance is approximately 300 meters in outdoors open areas, 4 ringtones to choose fromEasy To Install: The voice intercom doorbell is easy to install and do not require complex steps to complete the installation, no wiring and No punching requiredLong Distance : With strong signal penetrating, this device can transmit signals over hundreds of meters in open areas, ensuring timely receipt of calls across different rooms or floorsWide Application: The electronic doorbell is suitable for home, restaurant, cafe, apartment, courtyard, company, etc,The indoor unit requires 3x 1.5V batteries (not included), outdoor unit uses a plug (not included) Specification: Material: ABS pp Size Chart: Yellow Outdoor Use: 8 cm x 5.2 cm x 2.3 cm/3.15 inch x 2.05 inch x 0.91 inchSilver Indoor Use: 8 cm x 5.2 cm x 1.3 cm/3.15 inch x 2.05 inch x 0.51 inch Package Includes: 1x Outdoor Use Doorbell1x Indoor Use Doorbell1x Instruction manual1x Back Adhesive11x Screws Note: Please allow slightly errors due to manual measurement and different monitors.