How to make
The size of a fabric is 14cm×40cm. Seam allowances (1cm) are included.
Fold a hem (1cm), and fold the fabric in half. Then stitch 1mm from both ends.
When making creases, it is recommended to use an sewing ruler for iron. The folds are neat and the finish is nicely.
Fold over the top and bottom edge (5cm), and sew the side seams (1cm).
Then sew the edge with zig zag stitch, and turn the case inside out. It’s done.
Making movie is the following.