Eureka Colorful Teacher Welcome Cards Mailable Postcards for Teachers, 4'' W x 6'' L Includes (36) identical 'Welcome' teacher postcards. Each welcome postcard measures 4'' W x 6'' L. Welcome your students to your class before the school year starts with our cute and colorful postcards! Have students fill out a card when they arrive to the first day of class as a fun and engaging way to learn a little about them. These cards are a fun inexpensive way for teachers to stay in touch with students and parents and the back looks like a standard postcard so a personal message can be added.