I have to agree with the review of 'AlanP' in that these are OK, but no more than that.
I know that as a single use item, they are not going to be robust, but they are quite flimsy and have to be handled with care when fitting, or the elasticated collar will snap, making the item useless. That said they have done the job, keeping grubby footprints off our porcelain floor tiles, when we or tradesmen are popping in and out of the house.
So, in essence you get what you pay for, cheap, disposable and do the job, just handle with care when fitting and don't try to fit them over size 10 work boots!! Just in case you had not noticed, these are shipped from Hong Kong, so next day delivery is not a likely option!!