 OEM product keys are priced lower than their retail counterparts, especially as they are purchased in bulk quantities.But they use the same software as retail versions of Windows.They are primarily for PC manufacturer OEMs and system builders, and as such are typically sold in volume licensing deals to a variety of manufacturers (Dell, HP, ASUS, Acer, Lenovo, Wistron, Inventec, Supermicro, Compal Electronics, Quanta Computer, Foxconn, Pegatron, Jabil, Flex, etc.