What size is my Whirlpool washer & dryer?

We are trying to sell my Whirlpool Duet Sport washer & dryer. I have looked all over the manual and the washer and dryer and I can't find the size anywhere. I have heard everything from 3.3 cu. ft to 3.8 cu. ft. The guy interested in buying it of course wants to know the specific size. How can I find out the size for both the washer and dryer? The model number is WFW8300SW04.