(MONEY Magazine) – With interest rates bottoming out and perhaps ready to inch up over the next six months, you should beware of gimmicky certificates of deposit that banks are now pushing supposedly to help you cash in on the coming upticks in rates. One example is the so-called step-up CD, which lets your interest rate climb automatically in a series of small steps. Problem is, it actually doesn't help you capitalize on rising rates, since the increases are predetermined and don't change if, say, rates shoot up. What's more, over their lifetime, step- up CDs may pay less than standard products. At PNC Bank Pittsburgh, for example, the three-year step-up CD starts at 2.95% and climbs every six months to a final rate of 4.3%. While that ultimate rate is higher than the 3.8% paid by the typical three-year CD, the average yield over the three-year period is only 3.6%. Lesson: Unless an unusual product offers a clear advantage, stick to conventional six-month CDs that pay a predictable return (currently 2.84%) and leave you free to reinvest at a higher rate later when rates climb.