I had never come across this type of card until today when I stumbled across two of them on Etsy. Measuring an incredible 3.5 in x 11 in they must have been difficult to send through the mail without suffering damage. According to the Tuck Database they date from 1907 and were issued as a set of six. Reasonably priced at €9 each plus shipping (from the USA) I decided not to take the risk of damage – even in a card backed envelope. If you’re interested they are here.