I have this one that I use for myself. It is has various nature sounds, and then a "white noise" sound that on the previous model that I had, was called "Waterfall" - it sounds like a waterfall, or a loud fan, something like that. It can be set for 30, 60, 90 minutes, or for non-stop. It also has sound cards you can buy to customize it. I've had it for years and use it every night and it still works great. My cat knocks it off the nightstand on a regular basis, and it still works.
My H is a night owl, so I can't fall asleep easily because he's up and watching TV in our small apartment. Now that I'm pregnant, I've had early-wake insomnia so having it set on "non-stop" helps me not wake up in the middle of the night.