An excellent choice.  Large and durable.
These are excellent heavy-duty water-resistant bags.  I use them in the back of my pickup for carrying luggage and other things that I want out of the weather.  I carry two, and they fit under the seat in the cab when I'm not using them.  They were the largest ones I could find at the time, and fitting on a cargo carrier was not a concern, but if you are using them for that, please make sure they fit your carrier.  They come with straps and attachment points for carrier use, as well.
Rating: 5 stars