what is 0x size
0X is what it is; list as such. 0X is bigger than XL -- wider and boxier in cut even if the measurements seem similar. It may or may not be a 16W equivalent depending on manufacturer. I've seen size charts where a 0X is 12W, 14W 16W and 18W. I'd just list it as what it is -- those that wear it will find it.