People always have questions to ask about twins - are you identical being one of the key ones, even if it's obvious that you're not? The message inside reads 'Happy Birthday!'.
The card is a white square card, 14.8mm x 14.8mm, approximately 5.75 x 5.75 inches. It comes with a white blank envelope. It will be posted to you in a board-backed envelope marked 'Please do not bend'. No plastic packaging is used.