The HoMedics MyBaby Deep Sleep SoundSpa is scientifically engineered to help your baby fall asleep and stay asleep. Choose from three patented white noise programs, which mask distractions while comforting baby. You can also choose from different nature tones, including: Heartbeat, Soothe, Mask, Calm, Ocean and Twinkle Twinkle. The MyBaby Deep Sleep SoundSpa includes an AC adapter, but it can also be powered by 4 AAA batteries for portable use. Features an auto-off timer that can be set to 30, 60, or 90 minutes, making it perfect for nap time.