Marpac Sound Screen & SleepMate 980 combines American ingenuity and craftsmanship to create a lightweight, yet durable appliance capable of many years of reliable service. Marpac 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. The dual speed 980 is made of durable plastic housing suitable for travel or use in the home or office.