For longtime income investor Jenny Harrington, slow and steady is key to success. The Gilman Hill Asset Management CEO revealed to CNBC PRO’s “Art of the Trade” that her best trade ever is an oil and gas pipeline company that has allowed her to double her money every nine years, thanks to its hefty dividends. “I’m collecting really, really consistent income that my clients can depend on. That to me is as good as it gets,” Harrington said. “Their objective as a company for their shareholders is to pay out a high cash yield…. they’re not trying to grow at stratospheric levels.” Harrington, a trader on CNBC’s “Halftime Report,” has been running her dividend portfolio for 15 years at Gilman Hill, overseeing more than $800 million in client assets. Her return objective is plain and simple: 5% dividend yield plus capital gains. Watch the video above for the trade.