The 2pc Napa Balkamp 725-1286 Black Male Dust Cap is designed for hydraulic quick disconnect fittings on tractors. These dust caps are compatible with NAPA brand equipment and serve as protective covers to prevent dirt and debris from entering the hydraulic system. The units come in a pack of two and feature an interchange part number of 5209-4M. Additionally, there is a California Prop 65 warning associated with this product due to potential health hazards.