Hip Hippo Hooray Hippopotamus Birthday Party InvitationsSome features of our Birthday Invitations: Professionally printed on 80# cardstock paper so you feel the quality. An invitation in the mail is more fun to receive than an electronic invite! Easy to use because all you have to do is simply fill in and mail out. 20 cards and 20 white envelopes included. 5 X 7" so they have bigger visual impact (most other invites are much smaller). 100% Manufactured in the USA, we use local professional print shops and