Balboa AX10A1 Auxiliary Topside Panel [w o Overlay] (G8911) magnacraft The Waterco Hydro II TM The Waterco Hydro II TM hub assembly with laterals is designed for compatible 18 inch and 21 inch filter applications where the internal collector hub and lateral structure need replacement 5 HP impeller is designed for compatible pump applications where restoring the correct hydraulic component is part of a proper rebuild it works well in setups where the matching face is handled separately or where the installer needs to pair the panel body with the correct overlay for the exact final function layout giving compatible systems a dedicated secondary control point without requiring the main panel to do everything