【10 SMOOTH & NATURAL SOUNDS】White noise, ocean waves, bird sounds, heartbeat sounds, clock sounds, cricket sounds, running water sounds and 3 lullabies. Choose sounds according to your preferences and needs to create a quiet environment and let you fall as sleep quickly and rest completely. 【3 TIMER & MEMORY FUNCTION】The auto-off timer can be set for 15/30/60 minutes or continuous play as needed. The memory function will automatically remember your previous volume, sound and timer when restarted. 【AUTOMATIC DETECTION OF WHITE NOISE】 Without power on, press and hold Auto for 2 seconds to enter the noise detection for 10s. If there is noise around, it will automatically turn on the music and stop after 15 minutes. The detection will be cycled. The detection distance is 6-10m. 【VOLUME CONTROL BUTTON】The Next/Last Song Button. Press and hold is volume plus/down. When to the maximum/minimum, a prompt tone will be played, indicating that it has been to the maximum/minimum. At this time, you can release. Need more attention, the volume will decrease with the decrease of power, when the volume is low, please recharge the machine in time. 【COMPACT & PORTABLE】With 3.66*3.15*1.1 inches, easily fitted into your handbag or suitcase, making it perfect for home, office and travel use. It also comes with a hanging rope that is suitable for stroller, cribs or other places that can be hung up. And equipped with a rechargeable battery. No need to plug and socket connection, you can use it anywhere.