Buy Lipi. 6mm screw is being re-trimmed and being used for replacement. COSPER is good because the brush part is expendable. However, it may be broken from the connection part so it is better if reinforced.
I purchased for the first time
There is the hardness of what I thought and the hair "nylon".
I wonder if my mother is scratched if it is slightly softer ~.
I was not satisfied with the place of my use.