Designed as a 5"x7" (12.7cm x 17.8cm) card to fit in a standard A7 envelope, the design is scalable for other sizes (please note that highly-detailed designs may prove difficult if scaled too small).
It looks great on white card-stock with a colored insert, dual-color paper, or colored construction paper. The design is also provided in a file separate from the card boundaries in case you'd like to laser-cut it or print it in some other context.