1.20 Soothing Sounds: Enjoy a selection of 20 soothing sound sources right out of the box, including 5 tracks with white noise, 5 gentle music pieces, 9 nature sounds, and 1 heartbeat tone. No downloads or connections are required. Just turn it on and enjoy the soothing sounds. 2. Convenient Timer Low Battery Alerts: Users can set a timer for playing time with four options: 30 minutes, 60 minutes, 90 minutes, or turn it off manually. In addition, the low battery warning system emits a beep when the battery is running low, ensuring you always have sound when needed and can charge in time. 3. LongLasting Battery Life: Equipped with a 1000mAh Li battery, this baby and child sleep machine provides an impressive battery life of 9 to 14 hours on a single charge. Full charging takes only 3 hours, allowing longer use without the need for a power outlet, making it suitable for travel or bedtime routines. 4. UserFriendly Features: The white noise travel sleep device is ready to use without WiFi or additional network setup. With a maximum range of approximately 20 meters, you can flexibly place it at home, in the office, or on the go.