Flush Mount Structural Post is compatible with RDI Endurance, Finyl Line, Titan Pro Rail, Avalon Aluminum Railing and Metal Works Excalibur* systems. Note that Excalibur and Avalon Aluminum Railing both include their own system of posts, but if you want a mix-andmatch look, structural posts (sleeved with vinyl post sleeves, aluminum sleeves, or Transform post sleeves) can be used with both systems.