Includes two sizes of magnetic, dry-erasable bonds! Teachers use the large demo bond to model equations on the classroom whiteboard. Students use the smaller bonds to practice on lap boards. Includes 1 large demo bond and 4 student bonds (each bond die cut as a solid piece). Also can be used with our Magnetic Two-Color Counters. Student boards and counters, sold separately. Demo bond measures approximately 15.5" x 12.3". For ages 5+ and Grades K+.