We bought this noise machine to drown out distracting sounds in order to help our newborn to sleep better. It definitely helps to sooth her to sleep and helps her stay asleep.This noise machine uses a standard power adapter which has a cable around 3ft. It doesn’t have an internal rechargeable battery, and you can’t use batteries. So it does need to be plugged in at all times to work.You turn the unit on by pressing and holding down on the top for a couple seconds. I happen to like this feature a lot. It makes it easy to turn it on and off in the dark. Yes it does make a beep sound when you turn it off and on, but it has never been an issue for us. You can also use the night light feature by tapping on the top of the unit. Once again I like this feature as it makes it easy to use in the dark. The light doesn’t illuminate the entire room, but is bright enough to help you walk around the bedroom at night without disturbing your child with a strong light.There are 14 sounds on this machine: White noise, Pink noise, Brown noise, Fan noise, Clothes dryer 1, Clothes dryer 2, Crickets, Singing birds, Ocean waves, Thunderstorm, Water stream, Twinkle twinkle little star, Hush little baby, Rock-a-bye baby. The white, pink, and brown noises seem to be our newborns favorite. You can scroll through all the sounds by using the + and - buttons. These sounds can be played indefinitely through the night or you can set a timer from 15 to 120 minutes by using the button with a "T".Speaker quality seems to be good on this unit. Hold down on the + and - buttons to change the volume. Even with the volume all the way up the sounds are still crisp and clear with no distortion. The volume gets plenty loud for our liking as well. Most of the time we use it a click or two down from max volume.I really like the way this unit functions and the night light feature. Although it does not have a ton of different sounds on it I feel like it has the most popular ones. For the $20 dollar price tag I would buy it again and also recommend it to others.