Size: Cards measure a generous 4“ x 6” when folded. Envelope size is 4.2" x 6.2". Blank on the inside: Blank Inside. Each pack Includes 50 thank you cards and 50 envelopes. Using oil pen (permanent or marker) will get a better writting effect, because these cards are made of smooth art paper. If you use normal pen, pease wait a moment until the writting dry. Cardstock: All cards are made of heavy-duty paper at a grade of 300 grams per square meter. The envelope is self-seal design , just peel and seal to create a strong lasting seal. You can also secure with sticker. Safari thank you cards: Safari thank you cards are suitable for your baby shower, baby sprinkle or birthday party. Jungle Safari Thank You Cards With Envelopes, 50 Jungle Animals Baby Shower Thank You Notes