I really like these. They were bought for some big leather fleece lined winter boots that had gone a bit whiffy. The smell really does go if you keep them in for a couple of days. I think that they pick up any damp in the shoe so they could be used for ski boots to. Size wise they fit fine in adult shoes and from about size kids 11 (which is a 29? I think).
Bought these for use in my new boxing gloves. Only been using them a few weeks but so far the gloves still smell fresh and new, no hints of odour build up. Seem good value as the bags are large, but time will tell