Cover from the USA!

Today I got a cool cover from the USA! The cover is unique because it was sent from the J.W. Westcott II. The J.W. Westcott II is a mail boat that delivers mail to ships transiting the Detroit River. It is based out of Detroit and is the only floating post office in the world that delivers mail to ships on the move. Mail is often transferred between ships via a pail and pulley system. The zip code 48222 is used exclusively by the floating post office. The reverse of the cover features a special pictorial postmark.