Microsoft is a popular example of a company that issues its Windows operating systems for use by OEM computer manufacturers via the Bundling of Microsoft Windows. OEM product keys are priced lower than their retail counterparts, especially as they are purchased in bulk quantities, though 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.). These OEMs commonly use a procedure known as System Locked Pre-installation, which pre-activates Windows on PCs that are to be sold via mass distribution. These OEMs commonly bundle software that is not installed on stock Windows on the images of Windows that will be deployed with their PCs (appropriate hardware drivers, anti-malware and maintenance software, various apps, etc).