 Rain tires are cradded tires like regular tires on your car, whereas NASCAR normally runs on slicks, which just will send you straight into the wall on a wet track. So they put these rain tires on, which they've used on road courses, and so, of course, runs on rain tires all the time in sports cars. But they really hadn't tried them except for 20 laps at Richmond earlier this year at the start of the race.