A pressure canner is a specialized kitchen appliance used for preserving low-acid foods, such as vegetables, meats, and poultry. It operates by sealing food in jars and using steam pressure to raise the temperature above boiling point, effectively killing harmful bacteria and ensuring safe preservation. These canners come in two main types: weighted gauge and dial gauge. Weighted gauge canners use a weight to maintain pressure, while dial gauge canners have a pressure dial for monitoring. Proper use of a pressure canner is essential for safe home canning, as it helps prevent foodborne illnesses.