Skull invitations Printed with Heavyweight, Thick Cardstock! Set of 50 Wedding Halloween Skull Themed invitations printed on thick 120 lb Matte cover weight thick cardstock in vibrant quality colors. These Skull / Halloween Invitations include white square flap envelopes with your return address on the back flap. Invitations measure 5x7 inches. The RSVP cards are postcard style and do not require envelopes. RSVP cards measure a large 5.5x4.25 inches!