Size: Our birthday invitation cards are measures 4 x 6 inches & the envelopes match the invites, proper size for use and keep. Package included: there are 20 pcs invitation cards & 20 matching envelopes inside the package. Material: Our birthday invitation cards are made of heavy gram writing paper, easy to fill in & also with the printing technology, it shows nice quality & exquisite details. Applications: These birthday invitation set are thoughtful party supplies when you are preparing a birthday party, with invite cards & matching envelopes, convenient to use and eye-catching designs, impress your guest with it and enjoy your birthday party! Size: Our birthday invitation cards are measures 4 x 6 inches & the envelopes match the invites, proper size for use and keep. Package included: there are 20 pcs invitation cards & 20 matching envelopes inside the package. Material: Our birthday invitation cards are made of heavy gram writing paper, easy to fill in & also with the printing technology, it shows nice quality & exquisite details. Applications: These birthday invitation set are thoughtful party supplies when you are preparing a birthday party, with invite cards & matching envelopes, convenient to use and eye-catching designs, impress your guest with it and enjoy your birthday party!