• See and hear to visitors, receive photos through your smart phone app when visitors ring the doorbell• Easy to install No wires needed. Battery can be replaced easily.• Requires a Smartphone either an Android or iOS and Wi-Fi Connection• The unit works as a traditional wireless doorbell whether or not Wi-Fi is operational.• When a visitor rings the doorbell, a snapshot will be taken and sent to your smart phone• Image sensor 4 inch CMOS with 2.0 MP resolution• Transmission through RF 2.4 GHz between indoor and outdoor units and Wi-Fi 2.4 GHz• Power Indoor Unit AC 100-240 Volt | Outdoor Unit Battery AAA x 2