... 1.Material:99% Alumina 2.Wear resistance, 3.High mechanical strenght 4,Custom design 5,Eco-friendly,favourable price FeatureAlumina ... ,high temperature tolerance,precision process, high mechanical strength, good chemical stability,good smoothness, mechanical seal good, and so on.Property ItemsUnit95 ... Perpendicularity and other specification are upon your requirements. Alumina ceramic small ring