This is a classic Italian parcel post (Pacchi Postali) stamp, denominated at 100 Lire, issued in the mid-20th century. The design features the iconic post horn, a traditional symbol of postal services, along with the inscription "Sul Bollettino" indicating its use on the parcel dispatch note. Marked as the “1a Parte” (first part), it was part of a two-stamp system required for parcel postings. Printed in deep blue, this issue is a distinctive piece of Italy’s postal history, especially for collectors interested in specialized postal services. A fine example of functional yet elegant Italian philatelic design.