100 Days Shaper Shirt. Happy 100th Day of School Shirt. Makes a fun gift for students, parents and teachers to celebrate 100 days of school. Celebrate being 100 days smarter in this cute t-shirt! This cute 100 days of school t-shirt makes a great gift for an elementary, primary or grade school teacher, principal, coach or student. Click our brand name for more grades, styles. Lightweight, Classic fit, Double-needle sleeve and bottom hem