This operation instruction is for Fiberall V311B auto battery tester and diagnostic tool. The diagnostic tool is for vehicle with 12V battery and the article tell user what should be prepared before test. It introduce each part of the battery diagnostic tool and help the user know the meaning of each press key. Main parameters makes user know basic information of the diagnostic tool. The main content of the article is to tell the user how to operate each function, including battery test, start test, charging test, setting of diagnostic tool, buzzer switch, screen capture settings, diagnostic tool self-test, print. Each part is with detail description and screenshot, user is able to operate the battery diagnostic tool easily with following of this article. User can find user manual with the same content of this article in the package of V311B auto battery tester and diagnostic tool.