A filter, often referred to as a strainer, is a device used to separate unwanted materials or substances from a liquid or gas. It typically consists of a porous material that allows the desired fluid to pass through while trapping larger particles, debris, or contaminants. Filters are commonly used in various applications, including water purification, air conditioning systems, and industrial processes. Filters come in many forms, such as mesh filters, paper filters, and cartridge filters, each designed for specific tasks. They play a crucial role in maintaining the quality and safety of fluids, ensuring that systems operate efficiently and effectively. Regular maintenance and replacement of filters are essential to ensure optimal performance.