Hydraulic reservoir filter breathers are components used in hydraulic systems to maintain the cleanliness of the hydraulic fluid and regulate air pressure within the reservoir. Think of them as a combination of a filter and a breather for the hydraulic system. They work by filtering out contaminants, such as dirt, water, and debris, from the air entering the reservoir, preventing them from contaminating the hydraulic fluid. At the same time, they allow air to enter and exit the reservoir (or 'breathe'), ensuring that pressure doesn't build up excessively inside. Hydraulic reservoir filter breathers play a crucial role in preserving the quality of the hydraulic fluid and promoting the efficient operation of the hydraulic system overall.