Go to the Interstate Batteries web site to learn the definitions of all the battery specs and then buy one which meets or exceeds Volvo's. All batteries are NOT the same at all. The cold cranking amps (short circuit current) and reserve capacity (Amp-hour capacity) are both important (especially if you live in a cold climate or have high-powered stereo equipment or other accessories in your car). These differ widely among batteries, increasing with higher price. If you compare different batteries, pick them up. The good ones are much heavier.

I'm no shill for Interstate - never even had one. I don't think the brand matters as much as the price range. My original Volvo one lasted 7 years or so. I've had better or top of the line batteries from Exide, Eveready, Motorcraft (Ford) or Sears and all were ok.