Any idea what this is?

Picked this up today from a free box! One of the ladies thought it might be to keep boots upright but frankly I'm a little stumped. Any ideas? There are several pieces of cardboard shaped the same as the vinyl holder inside additional plastic sleeves. Thanks!

 

I've seen opera gloves with those type of cardboard inserts, to keep them flat when storing.

 

They are four inches wide at the smallest part so I'm thinking that's too big. Thanks.