Shodo/Shuji Supplies... Others This is a new item. One small Two large One extra-large A set of 4. These are brush caps for calligraphy brushes. Regarding the extra-large size: I believe that the large and small sizes generally cover the calligraphy sets used in schools, but this is for those who are concerned about the large size. Extra-large: Inner diameter 17mm Large: Inner diameter 14mm Small: Inner diameter 9.0mm By putting these on the brush after use, you can store it without making a mess, and it can be used immediately without drying out for about a week. Made of plastic