I'm super happy with this waterless diffuser. The photo on the website makes it look like it uses a micro usb charger, but the one I received had a usb-c charging cable, which was amazing! The diffuser works very well. It is completely silent, except for a very faint spray sound when it sprays out the mist... but the actual device itself is silent. There is no mechanical noise or humm or buzzing or anything. I have been using it for sleep, and also just around the lounge room during the day. I love that it has an internal lithium battery, so I can unplug it from the charger and use it in places where there is no electrical socket in the wall. The light can be turned off, but I have enjoyed leaving it on overnight, as it is quite dim and soothing. I'm usually very light sensitive, but this one doesn't keep me awake.