I don't think Rock Auto stocks any product themselves and as such they are not a conventional retailer. They seem to have contacts with many of the jobber warehouses in the industry. Rock Auto gathers all of the inventory listings for those many warehouses under one user interface, then directs your actual order for drop-shipping direct from whichever warehouse is providing the inventory. Typically they are also optimizing for shipping distance/cost. If you order a bunch of different products from different brands on one order you will see multiple warehouse locations and multiple shipping costs. The closeouts are probably the highest risk items as the actual suppliers are sweeping the last of their inventory out the door .... and it may not be "first quality". As a business person I find their business model fascinating.