1. Similar brass instrument to the postal horn

2. Line or sequence of postal horns

3. Letters and packages handled by postal services

4. Activity involving the use of a postal horn

4. System for collection, sorting, and delivery of mail

5. Sibilant sound made by a postal horn

5. Musical instrument often used as a symbol for postal services

6. Written message attached to a package or letter

7. Part of a postal horn that amplifies sound

7. Category of musical instruments including the postal horn

8. Small adhesive used to prepay postage

8. Closure for envelopes or packages sent by mail

9. Spiral shape found on some postal horn designs

10. Characteristic of a well-played postal horn

11. Action required to fit a postal horn into its case

12. Termination point of a postal horn

13. State of a postal horn without any fingerings

14. Part of a postal horn mouthpiece

15. Jazz style often accompanied by a postal horn

16. Action to coil or cover a postal horn

17. Container used to store and protect a postal horn