Of the 29 models of face - masks provided by US industrial and equipment supplier 3M 's flagship store on Tmall.com 26 were sold out or unavailable on Wednesday .
Tmall.com is a business - to - consumer shopping platform .
Of the 29 models of face - masks provided by US industrial and equipment supplier 3M 's flagship store on Tmall.com , a business - to - consumer shopping platform , 26 were sold out or unavailable on Wednesday .