The Leica EM HPM100 High Pressure Freezer is used for freezing aqueous specimens for examination of the specimens with an electron microscope, a light microscope or other surface-analysis methods, such as atomic force microscopy, secondary ion mass spectrometry or photoelectron spectroscopy. Additional preparation stages may occur between freezing and examination. Specimens are frozen with liquid nitrogen at a temperature of –197 °C under a pressure of 210 kPa.