Color: White - Material: Plastic - Install two AAA batteries for receiver and transmitter move the switch to '1' and '2' ('0' on transmitter is OFF '1' is low detecting sensitivity '2' is high detecting sensitivity '0' on receiver is OFF '1' is low volume '2' is high volume) - Transmitter has the same model with Doorbell Button - No wires or cables required - Place transmitter near baby the receiver can be placed or carried within the range of wireless signal receiving (the detecting light would twinkle every 5 seconds) in view of electricity saving and the possible effect of wireless to baby you can switch 'Test ON' to 'Test OFF' to turn off the test signal which won't be sent until the baby cries - Humanity design once the baby cry or other noise occurs the receiver may start to make electronic crying noise - The max reception range is about 80-100 meters - Each powered by 2 x AAA batteries (not included)