It provides an alert with loud sound and flashing light & notification icon together with strong vibration (by wake up pad) when there is an incoming telephone call and when someone press the doorbell.
SUB-1G RF frequency with wireless transmission range up to 300m / 1,000ft (direct line of sight)
The receiver can pair up to 6 transmitters, capable to add other transmitters to expand the system

Wireless Doorbell Press (Transmitter)

IP44 Water splash proof design
It can transmit a wireless signal to receiver when the button was pressed
Place outside the door act as a doorbell press or indoor as a calling button
With mounting bracket
Low battery indication on receiver unit

Wireless Telephone Call Alert (Transmitter)

Simple operation, plug the device and the telephone line into the included RJ11 splitter, then into the telephone sockets
it can transmit a wireless signal to receiver when an incoming telephone call comes
Low battery indication on receiver unit