A USB 3.0 drive is preferred as it can speed up the installation process.
Google Chrome, Microsoft Edge, Vivaldi, and even Opera are a few examples. Access to the Chrome Web Store: You need a browser that works with the Chrome Web Store to install the Chromebook Recovery Utility and download ChromeOS Flex.A Windows or Mac system to create a ChromeOS Flex Installer: You'll need a PC or Mac different from the one you're installing ChromeOS Flex on to download the ChromeOS Flex operating system and create a USB installer for it.