It is the automatic bidding system that places bids on your behalf. All you have to do is set it up by indicating the maximum price you are willing to offer.
If you ever want to cancel it, just click on the appropriate command that appears in the bidding box.

The proxy bid system will act as follows:

 

- If a counter-offer is placed;

 

- If your bid is surpassed;

 

- If the counteroffer is equal to the value of your Proxy Bid.