The LectroFan Alpha is a clip-on white-noise machine that weighs four ounces and runs more than a day on a USB charge, so it lives in a carry-on instead of on a nightstand. Its fan, pink- and brown-noise, ocean, and heartbeat tones are generated rather than looped, so there’s no repeating seam to notice once you’re trying to fall asleep in a strange hotel. Cool Tools flags it as the travel version of the noise machine a lot of people already keep at home.