There are several types of cryogenic freezers used in Histology: - Ultra-Low Temperature Freezers: These are mechanically driven freezers that reach temperatures as low as -86°C. - Chest Freezers: Horizontal freezers ideal for large-volume storage. - Upright Freezers: Vertical freezers that provide easy access to stored samples. - Liquid Nitrogen Freezers: These are the most common for achieving the lowest temperatures and are used for long-term storage.