Doesn't run on A/C power so it's likely to run through batteries quickly
I bought/received two of these. The first one required a return because while the green light powered on, the speaker wasn't working and I was unable to hear any noise. The second one arrived without any problems, but I realized shortly thereafter that this isn't the ideal sound machine. I planned on using it every night for my son. However, it runs on batteries and I began to worry that they'd eat up those batteries relatively quickly. I ended up keeping the device because it was my oversight that this doesn't have any support for A/C power, but we stopped using it right after. I bought another sound machine for my baby with a plug this time. Now all my kids have identical sound machines which works fine for us.
amazon reviews