PowerFilm R-42 42 Watt Rollable Solar Panel Charger Amorphous silicon thin film flexible solar panel is extremely lightweight at only 3.2 lbs (0.8 kg), yet provides 42 Watts! Durable & weatherproof, PowerFilm solar panels are designed for US military use. Ideal for RVs, cabins, homes, boats, for back-up and remote power use. 100% made in the USA, PowerFilm's thin film solar panels are manufactured in Ames, Iowa. High performance solar charger charges 12V battery systems directly and works well in low light conditions and on cloudy days. Even works when partially shaded (a condition that causes other solar panels to fail). Built-in blocking diode protects against battery discharge at night.