White Noise Machine Has been the best helper in my studio and for my grandchildren. I love this machine because I can either set a timer or have it going all the time. This machine does plug into the wall. I have a grand daughter that loves sound when she is sleeping. So we plug this in when she sleeps and it works so good. I also use this the entire time during a newborn shoot. I think a baby needs to have sound when sleeping so they don't get use to everything being quiet. I did get this one on Amazon. I know there are a lot of ones you can get. This one just has the sounds that I use the most.