bidding agency. That is, if you want to buy something by bidding, you have to contact them and issue a tender (in fact, it is to set the conditions for the products you want to buy, and the tender should be published online). After seeing the tender of the bidding company, the bidder (manufacturer or agent or others) will spend money to buy a copy (very cheap), and then bid within the specified time, and their products will be graded by experts. This will ensure that you can buy your favorite products. This is what they do. I suggest you look at some laws and regulations in our country, there are many. The bigger one is the bidding method. There are also some local regulations and normative documents.