Google Translate says:
kleid's original basic 2mm grid note--easy to both write or draw illustrations. Comes in an A5 size using the highest quality paper in Japan, "OK Fools". OK Fools paper allows the pen to glide on the paper, offering great ink absorbency which makes this book have great chemistry with fountain pens. The paper also has sunemo texture and see-through features which can only be found in high quality paper.