My son used this for just under a year when he was in 5th grade. We had rented equipment from 2nd grade until we bought this, and the size was about the same as the rental, so it was a size that could be used from around 2nd to 5th grade. He is currently 140cm tall and slender. This size still fits him perfectly, but I am selling it because I purchased a set one size larger due to a connection with an acquaintance who owns a bogu (protective gear) shop. He was busy with entrance exams and other lessons, and didn't go to the dojo very often, and there were few children who hit the torso, so there are few scratches and I think the condition is good. I bought this after it was recommended by a bogu shop that children in this area go to. It is a Yamato-do (torso). I used the measurement method in the attached image to measure the size. According to this, it seems to be a SS size. A 30cm Torso height B 27.5cm C 13.5cm Chest height D 19cm Chest width E 18cm F Torso circumference (half circumference) 54cm