Sellers start by listing a minimum price, or starting bid for one item, and the number of items for sale. Bidders specify both a bid price and the quantity they want to buy. If there are more buyers than items, the earliest successful bids get the goods. Higher bidders are more likely to get the quantities they've asked for. Proxy bidding is not used in Dutch Auctions.
Bidders can refuse partial quantities.
For example, if you place a bid for 10 items and only 8 are available after the auction, you don't have to buy any of them. The only exception to the requirement that all items be identical relates to trading card listings. Lots of trading cards need not be identical due to the nature of these sales in the trading card arena. Because there may be little left over after the high bidders get their share. In other words, if the lowest bidder requests a quantity of 3 pens, she may only get one since the first 9 pens have already been allotted to the higher bidders.