These are decent mats, they stick well and firmly (they don't make weird noises when you step on them). The material seems to be of good quality.
From what I understood from the search and ordering process, these mats are ordered from a factory in the Netherlands and they are the "unique" ones available on the market (unique meaning there are few producers of similar products).

Update after two years of use: Very good, they have remained in excellent condition (we don't step on them with shoes).