Three 1-meter white YKK zippers. How about for a nursery school futon cover? The zippers have top and bottom stops suitable for cover specifications. If you sew the zipper teeth to the outside, it will be less likely to get caught when zipping up and down. Also, when sewing, sew the top and bottom parts of the zipper attachment slightly before attaching the zipper, which makes it easier to attach. Then, finishing it in a bag shape is easy.