Q: what does it mean when it says one size, what size is it??
A: Hi,trin,one size means we have no other sizes for it. For one size or free size items ,normally fit size XS to M in Chinese size, but in order to confirm whether it can fit your own size, please check the product info under the item in description.
Then compare it with your own size to choose the proper size for yourself.
For your reference, please note that 1 inch= 2.54cm so you can convert the size accurately.