: SUNGOLDPOWER UL61730 550W solar panel monocrystalline grade A solar cells, the waterproof design ensures that the panel can be in all weather conditions. : 18BB 550W solar panels are designed for industrial and professional applications using scratch resistant anodized aluminum with a twin wall frame. The tough, sealed, aluminum frame will give you years and years of consistent, free power. : Easy Installation with pre-drilled hole. Corrosion-resistant aluminum frame for extended outdoor use. Suitable for Caravan, RV, Golf car, Electric car, Yacht, Boat, Tent or backpack etc.