A vertical autoclave is a pressure vessel used for steam sterilization in medical field. The “12×20” typically refers to the dimensions of the chamber, indicating an internal diameter of 12 inches and a depth of 20 inches. This top-loading design is space-efficient, making it ideal for facilities with limited floor space. The autoclave operates by using high-pressure saturated steam at temperatures typically between 121°C to 134°C to effectively kill all microorganisms, including spores, on instruments, media, and other items. It is an indispensable tool for ensuring the sterility of reusable equipment.