Features: 1) Designed for commercial solar water heating applications 2) Reliable, efficient, twin-glass solar tubes 3) Polyurethane insulation ensures good heating performance and minimal heat loss 4) Manifold cover\'\'s material: stainless steel or galvanized sheet 5) Frame material: 1.2mm thick all stainless steel 6) Easy plug-in installation 7) Can be connected in series to increase water heating capacity