Away on travel, this sound machine eases you to sleep with comforting "white noise." Because "white noise" contains all frequencies, it can mask the source of sleep disturbance, air traffic, street sounds or loud hotel guests. And, unlike other units that use recorded sound effects, this one modulates the white noise (proven to be effective in aiding relaxation) to offer a choice of rain, waterfall and surf selections. Slide controls for tone and volume. Fits into a toiletry kit or makeup bag. Comes with a nylon pouch. ABS plastic. Includes transformer, 6' cord. UL listed. 5 1/5" L x 4 1/8" H x 2 1/4" D. (1 1/2 lbs.)