Send This When Traveling, No Envelope Needed
Puzzle 6 of Words that Rhyme Piece of Cake Pack
Question is: Send This When Traveling, No Envelope Needed
and the answer is: POSTCARD
Word Meaning:
POSTCARD — (postal) A rectangular piece of thick paper or thin cardboard, typically used for sending messages by mail without the need for an envelope.
Definitions from Wiktionary.