Intended primarily for numismatics enthusiasts and collectors, the United States Mint proof coins are placed in plastic cases called lenses, each lined with foam inserts to nest the proof coins.

• 要用于钱币学爱好者和收藏家，美国铸币局证明硬币被放置在塑料案件所谓透镜，每个排队泡沫插入筑巢的证据硬币。