CH 1950 B46-B50 Pro Patria FDC italian no address

Switzerland 1950 B (Swiss National Fête and PRO PATRIA - issues)
FDC with italian first day issue cancellation "1.VI.50 BERNA - Giorno d'emissione", white envelope without address (subscription letter of swiss post), rarley, luxury conservation,
Catalog SBK B46-B50, Michel 545-549