Features:

• White Noise machine creates smooth sound of rushing air
• Great for attorney, students, restless sleepers, babies and more
• Blocks most sounds for privacy, Dual Speed for extra convenience
• Uses a fan to create white noise. No break in noise due to a digitally created loop
• Made in the USA

Editor Reviews:

Product Description:
Marpac combines American ingenuity and craftsmanship to create a lightweight, yet durable appliance capable of many years of reliable service. These sound conditioners create a consistent, smooth sound of rushing air. The tone and volume of the sound are controlled by simply rotating the "cap" and "collar" of the housing. This "white noise" sound effectively masks unwanted noises and creates a sense of calm, making it easier to concentrate, relax and/or sleep. These sound conditioners are recommended for restless sleepers, shift workers, infants, children, students, apartment dwellers, office workers (for confidentiality) and many others. We offer the single speed model 580A or the dual speed 980A, both in a durable plastic housing suitable for travel or use in the home or office.

Rating : - sound soothing barrier for overstimulated and sound-sensitive people
I bought the Marpac 980 A originally for my classroom. i work with kids that struggle with an increased sensitivity to noise. i also struggle with noise sensitivity. I LOVE THIS PRODUCT! For the area that it was placed in (where the loudest and most sensitive child sat) it did its job. However, ideally i would have needed at least 3 other machines to create the noise muting environment i was looking for. After school it was a life saver for me, because it enabled me to work on paper-work with less distraction. Now (my buddy) the 'Marpac' is residing in my apartment. I live in a major city that is very loud. It effectively mutes (but not extinguishes) sounds from inside the apartment unit and in the hallway of the building itself (i have placed it right next to the door). I just bought another one for my 'studio'/sleeping/living room as the street noise keeps me awake at night.
I know its tempting to buy the cheaper model... but the whole point of getting the more expensive one is that you have the option (which i have NEVER used by the way) of flipping the switch to the 'lower frequency' which is the frequency that the cheaper model offers. I am not sure why they even sell the cheaper model at all...
Oh, and this machine has quite literally been ON 24/7 since January 08 (its currently November 08 and there have been no problems.