CH 1981 Stamp Day Grenchen SO, card with imprint Torre 1981 cancelled 4.-6.12.1981 2540 Grenchen

Switzerland 1981 Stamp Day Grenchen SO,
official card "Tag der Briefmarke - Journée du Timbre - Giornata del Francobollo - 4.-6.12.1981 - Grenchen -
illustration Chappeli-Tüüfel, Offizielle Ausgabe VSPhV",
with red/black imprint: "GIORNATA DEL FRANCOBOLLO - ESPOSIZIONE LOCALE DI FILATELIA - TORRE 5/6 DECEMBRE 1981",
with Pro Juventute stamps, without address, cancelled "4.-6.12.1981 2540 Grenchen - Tag der Briefmarke",
not cataloged, luxury conservation.