CH 2021 W128 Stamp Day Horgen FDC ill. no address with signature

Switzerland 2021 W (Semi-postals and Special issues sold at an additional premium)
bloc Stamp Day Horgen 2021 (Tag der Briefmarke),
bloc on ill. FDC (format C6) without address,
with signature of the stamp designers Raphael Schenker,
cancelled "11.11.21 8810 Horgen - Ausgabetag - Journee d'émission - Giorno d'emissione", luxury quality,
Catalog SBK W128, Michel Bloc 80.