The one on the Large Rolling Duffel looks larger than the one GRF has.
Look at the patch in the center of two pouches. His doesn't look that big. It does have the same design.
It is indeed one of the removable bags on the front of the small rolling duffel. I find it very useful when traveling on those puddle-jumper turbo-prop things where you can take standard size carry-on luggage to the plane but can't take it onto the plane.
I figured they were the same accessories for the large and the small and didn't see the small in the database. Thank for the correction. Guess I didn't look close enough. The small rolling duffel is definitely my favorite Oakley bag.