I had the larger version of the CC Duster when I had my '41 Olds which I sold along with the duster.  Had it for years and loved it.  Bought another antique car and wasted no time getting the duster again.  It's great.  The secret to satisfaction and effectiveness is to do what it recommends before using it:  Let it sit on some newspaper for two days to absorb excess paraffin (and put a small weight on the brush head forward of the handle to equalize the brush weight on the paper and change the paper every so often to ensure absorbtion) and you're good to go with no wax streaks on the car.  Works like a charm.