Heat pipe vacuum tube: oxygen free copper, 0.7thicknessof pipe. high efficieny, quick temp. rising, low heat loss, no harm. Copper Heat Pipe with solar vacuum tube collectorFeatures of our heat pipe vacuum tube:1) oxygen free copper is used as raw material. first quality.2)Combine glass vacuum tube and copper heat pipe as one unit.3) With super conducting working liquid in copper heat pipe.4) ...