Which of the following is used to test a tank for oxygen content?

The atmosphere analyzer kit is specifically designed to assess multiple components of the air quality within a tank, including the oxygen content. This tool provides precise measurements that are essential for ensuring safety in confined spaces, especially in areas where gas might accumulate or displace oxygen. By analyzing the atmospheric composition, the kit helps determine if the environment is safe for personnel to enter, specifically checking if oxygen levels are within acceptable limits.

Other options may assess various conditions but do not focus on measuring oxygen content directly. For example, an oxygen detector might only detect the presence of oxygen without providing the full atmospheric analysis that the atmosphere analyzer kit does. Smoke testers are primarily used for checking leaks or smoke propagation, while vapor indicators are designed to detect flammable vapors rather than specifically assessing oxygen levels in the tank. Thus, the atmosphere analyzer kit is the most appropriate choice for testing oxygen content in tanks.