White noise machine

Yogasleep Dohm Classic White Noise Machine

Mechanical fan-operated white noise machine provides a constant fan noise with volume adjustment.

Please be careful! Borrowers are financially responsible for replacements upon loss or damage. Full replacement cost for this item is $62.

Noise machines that loop audio files of noises such as babbling brooks don't work because your brain will pick up on the pattern of the audio file's loop, which is just more mental stimulation to keep you awake. This machine's noise is made by a mechanical spinning fan, so there is no distracting pattern to the noise.
The outer case and top disk both twist to change the intensity/volume of the noise.
Not battery powered.