The drivers can be customized with proprietary information specific to each company using the drivers. In order to customize the drivers, a Vendor ID (VID) and Product ID (PID) are required. The VID is typically provided by the USB Implementers Forum. However, a PID can be requested from Silicon Labs that customers can use along with the Silicon Labs VID. The several utilities shown here are provided by Silicon Labs to modify the device and the installers. The most common application notes used are AN144 and AN220. The AN144 and associated software provides the capability to modify the contents of the nonvolatile memory of the devices.  AN220 provides the instructions necessary to modify the driver installer and the INI file that becomes specific to the end customer. This application note also comes with associated software (AN220SW) that provides a GUI to walk through the customization process. Once complete, the driver can be submitted to Microsoft for WHQL certification. The steps following show an example of the AN220 customization process.