A Custom Recovery is a specialized software tool used on Android devices that allows users to perform advanced tasks beyond the standard recovery mode. It enables users to install custom firmware, create backups of their system, and restore their device to a previous state. Popular examples of custom recoveries include TWRP (Team Win Recovery Project) and ClockworkMod. By using a custom recovery, users can easily flash new ROMs, which are modified versions of the Android operating system. This flexibility allows for greater customization and optimization of the device, enhancing performance and adding features not available in the stock version. However, using a custom recovery may void the device's warranty and carries some risks.