Yukon Performance steel spool for 8Dana 80 with 37 spline axles, 4.10 & up. Yukon performance spools are made from the highest quality materials to ensure high strength and long life in performance applications. Spools provide 100% power to both tires at all times and are a lower cost alternative to lockers. Spools are not recommended for street driven vehicles. Yukon Performance spools come with a one year warranty against manufacturing defects.