The Dohm Classic Sound Machine is a natural white noise machine that was first invented in 1962. It has two speed options for adjustable tone and is designed to help people sleep. Known and loved for generations, the Dohm Classic features our signature natural white noise and a simple plug-and-play design. Just choose high or low speed, then twist the cap to find your ideal tone. Features Signature fan-based white noise (Marpac Sound) Two-speed settings for adjustable volume Customizable tone with rotating cap and collar Plug-in only with 120V AC power cord