CALANDIS® Chinese Traditional Kung Fu Martial Arts Tai chi Slipper Shoes Black 41

How to find suitable size? , THAN I CAN BUY THESE SHOES , HELP IF YOU CAN, #JUJUTSU KAISEN TOJI

I am wearing these shoes since many years but this is the first time I noticed that the shoes fabric is different. It is not like traditional shoes fabric... ok it is also good but that fabric has another level of comfort...