The Allied Precision Piston Pins PN21 J-3 .003 are high-quality piston pins designed for engines. These pins are made by Allied Precision, a reputable brand known for producing durable and reliable engine parts. The .003 size indicates that these pins are precision-made to fit perfectly in the engine's piston, ensuring optimal performance and efficiency. Additionally, the rust shown in the picture indicates that these piston pins have been used and may require cleaning or replacement, but their quality remains high. Box mw1104