It will keep out the rain from the outside, but...
I purchased this for MFK-234, Mini Shell Case.
Since the MFK-234 comes with a splash-proof Inner Porch, I thought the Rain Cover might not be necessary, but it would be reassuring to have it.
It is small and foldable, so carrying it around is not a problem.
Since the Manufacturer's photo only showed the outside, I will upload a photo from the Tire side for your reference.
Since this Rain Cover wraps around the outside of the Mini Shell Case, it does not prevent mud and rain from splashing up from the Tire.
