Krytox XHT-AC and XHT-ACX greases are special high temperature greases with low oil evaporation that provide anti-wear and rusting protection, and are compatible with all elastomers and plastics. These greases have excellent lubrication over a broad temperature range, but are designed to work best at temperatures over 200 °C (400 °F). Krytox XHT-AC series greases are nonflammable, oxygen-compatible, and chemically inert. Krytox greases provide extended lubrication intervals and longer equipment life.
The Krytox XHT-AC series greases are an extension of the Krytox 240 series and Krytox GPL 22X series, but are designed to give higher performance in the 204–302 °C (400–575 °F) range. Krytox XHT-AC series greases contain sodium nitrite to offer anti-corrosion performance. These greases should be used below 320 °C (608 °F), where the polytetrafluoroethylene (PTFE) thickener could begin to melt. The base oil is an extremely viscous oil that provides good viscosity and lower evaporation at high temperatures. Krytox grease is made to a standard NLGI grade 2. PTFE is the standard thickener.