AIRE's River Pack is now teal in a teal color without the black bottom section, but we haven't swapped out the image yet. These are approximately 16" around with a rolled height that can vary from 27" down to 20", providing a maximum of about 5400 cubic inches. In round numbers rolled to 26", it works out to three cubic feet on the nose. Note that pretty much all the "3.8" drybags on the market are calculated by their unrolled dimensions, and yes, that is dopey. It's something NRS started decades ago and has become sort of a skewed industry standard.
This round-bottom bag is made from the same PVC coated fabric on the sides as the AIRE Tributary kayaks, with Rf welded seams throughout. These have shoulder straps, a waist belt, and a carry handle. The River Pack comes with a nylon stuff bag to keep it clean when it's not being used.