Because of its thermal stability and nonoxidizing characteristics, Krytox™ is a natural high-temperature lubricant. Krytox™ XHT greases are available with useful temperature ranges up to 360°C (680°F) for continuous use, with spikes to 400°C (752°F), when used in proper metallurgy with periodic relubrication. Krytox™ lubricants contain only carbon, oxygen, and fluorine. Because hydrogen is not present, these products are nonflammable. They will not burn or support combustion, even in 100% liquid or gaseous oxygen. Krytox™ performance lubricants are not only resistant to oxygen, but are inert to virtually all chemicals used in a variety of industries. They are insoluble in most solvents but are soluble in highly fluorinated fluids and in some supercritical fluids such as CO2. XHT-AC, XHT-ACX, XHT-RUF, and XHT-RUFX are anticorrosion grade greases that are typically used for machines that run for shorter durations with frequent starts and stops. Frequently cooled machines require anticorrosion additives.