Autoclaves use steam under pressure to sterilize materials, and the temperature of the steam can reach 121-134°C (250-273°F). This high temperature is necessary to kill all types of microorganisms, including spores of thermophilic bacteria, which are resistant to lower temperatures. The temperature inside an autoclave is controlled by the pressure of the steam, with higher pressures resulting in higher temperatures. The pressure inside an autoclave can reach 15 pounds per square inch (psi), which helps to kill microorganisms that may be resistant to high temperatures. It is important to note that the temperature inside an autoclave may not be uniform throughout the chamber. The temperature may be higher near the steam source and lower in other areas of the chamber. As a result, it is important to carefully follow the manufacturer's instructions and guidelines for the specific autoclave being used to ensure that all materials are adequately sterilized.