These baseball-themed invitations, inspired by a vintage baseball ticket, were originally designed for a friend's baby shower, but are great for birthday parties too.  The invitations are completely customizable and come with 15 ivory envelopes and one roll of red and white striped washi tape to seal the envelopes.  They are printed on ivory or white 67lb cardstock paper in red and black or red and blue ink, as depicted in the photos.