Crossword Puzzle Post-office device

Clue: Post-office device

Post Office devices (DATERS with 6 letters)
Post-office devices (SCALES with 6 letters)
Post office device (e.g. DATER with 5 letters)
Undeliverable letter, in post-office talk (NIXIE with 5 letters)
Post office objective? (KISS with 4 letters)
Special-handling designation at the post office (REGISTEREDMAIL with 14 letters)
Post office, to the postmaster (STAMPINGGROUNDS with 15 letters)
Post office hunk? (MAILMODEL with 9 letters)
Post office worker? (EDITOR with 6 letters)
Sight at post offices (FLAGPOLE with 8 letters)