Features: 2.4GHz digital wireless transmission, stable transmission signal. Built-in MIC and speaker for one-way audio monitoring, with nightlight function. High sensitivity, the crying voice is easy to be heard and to inform parents. Adopt frequency hopping spread spectrun (FHSS), Anti-interference and sound clarity Position the transmitter at a distance of about 1.5-2.0 meters from the baby. Open space transmission range up to 250M. Specifications: Transmission Frequency: Ism 2400-2480MHz Transmission Power: 17dBm Modulation Type: Power Supply: Built-in lithium battery Operating Temperature range: -10-and60 Storage Temperature: -40-and70 Material: plastic colour: White Package Contents: 1 x Transmitter 1 x Receiver 2 Cable 1 x User Manual (English) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm.