Self-Esteem Postcards Pack Of 15Send a personal message. Inspired Minds Postcard Booster Sets are intentional printed simple, yet colorful, to offer an impactful and creative way for teachers to help children gain self-esteem and build character for a successful and fulfilling life. Each post card has a special message printed on the back along with a blank area to write your personal message. Post cards measure 4.25 in. x 6 in.. Pack of 15.