# Companion OpenTX comes with a computer-based graphical user interface, OpenTX Companion, that runs on Windows, Mac OS and Linux. It is a great tool to try things even without a radio. It can speed up new model setups because the PC interface is not limited to a small screen and a few buttons. Companion will allow you to: * Download and install OpenTX transmitter firmware * Simulate transmitters and models (Try before you buy or fly) * Edit transmitter and model configurations * Backup the transmitter’s firmware, models and SD Card contents * Edit the OpenTX transmitter start up screen (splash screen) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://doc.open-tx.org/manual-for-opentx-2-2/companion.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.