# System Overview A **life time tester** (LTT) is an electric control cabinet, whose purpose is to perform **long term electrical tests** on various electrical devices (so called *devices under test*, or short DUT) under certain **environmental conditions** (temperature, humidity, etc.). One can say, it simulates the aging process or lifetime of an electrical device. The **IRS LTT software**, which comes with every **IRS life time tester** is composed of several parts. ![System Overview](/files/tOde7L55NuNqPca7qN2H) This is the documentation of the IRS LTT software, including the graphical user interface (GUI), the TestStand sub system and all other related components. --- # 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://docs.irs.systems/ltt/documentation/ltt-gui-manual/gettingstarted/system-overview.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.