Nos. 6-8: Byron Myers, Ali Perry, Brenton Taylor

Ages: 28 (Myers), 25 (Perry) and 26 (Taylor)

Location: Goleta, Calif.

2006 revenue: $15 million

Employees: 100

Year founded: 2001

Winning a business-plan competition at the University of California, Santa Barbara, prompted these friends to take their idea for an oxygen concentrator and form a company. Perry's grandmother had complained about the bulkiness and inconvenience of her old oxygen machine, so the trio designed a compact device to filter out the nitrogen from room air, eliminating the hassle of having oxygen tanks delivered. Inogen's machine can be plugged in anywhere or used on the go with a rechargeable lithium-ion battery. The company has sold more than 10,000 devices.

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Source: Inc.com

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