Originally Posted by
alan s
Topeak makes a yellow rain cover for $6 at REI, which rolls up and takes very little space. Doesn't fit the pannier version, but there may be a cover for that, as well. Definitely works best with fenders, as the bag is not waterproof.
My panniered version came with a cover IIRC. If not it was purchased as an additional accessory and given to me all as one gift. They are out there. That said, the trunk does hold up well to your run of the mill shower or sprinkle even without the rain cover. Not, waterproof, but it keeps things dry enough. Even when I used my Topeak trunk every day, I rarely used my rain cover.