關於「Postcard size mm」標籤，搜尋引擎有相關的訊息討論：

A Guide to Postcard Sizes and PrintingPostcards sized 4 x 6 inches are eligible to mail at the USPS's First Class Postcard Rate. Postcards that are 5 x 7 – 6 x 11 may qualify for the USPS's Standard ...缺少字詞： gl= | 必須包含以下字詞：gl=The Ultimate Guide to Postcard Sizes - Colortech In