This 8 1/2 inch square ruler is perfect for making a quilt for an extra-long twin-size bed for a dorm room.  The 8-inch squares that result from using a 1/4 inch seam to sew the squares together, which is standard in quilting, result in a 72-inch wide and 96-inch long quilt.  Some sources say 68-inches by 94-inches is the standard quilt size for the twin XL, but 72 by 96 leaves rooms for some shrinkage from the first washing and also from the final quilting.  This quilt will be 9 (8-inch) squares by 12 (8-inch) squares for 108 squares, total.  So this ruler is very nice and convenient for making quilts for dorm beds.