Related Clues:

• Some is third class
• Knight wear
• Word with voice or express
• Something you get Saturday, but not Sunday
• Armor
• Stamped correspondence
• Knightly wear
• Knights' garb
• 'You've Got --'
• Send, as a postcard
• It might be registered
• Regular post
• It may be express
• Postmarked pieces
• Push the envelope?