... Haining , Zhejiang province. we are mainly focus on solar water heaters. our solar water heater factory is in Yuanhua Towm.our company ... certificated.general specificationsMaterial: High Borosilicate 3.3 glass , aluminum fin , sealed rubber cirde .Outer tube dimension&thickness:Φ = 47±0.7mm &=1.6mm ... .6mmLength: 800mm , 1200mm , 1500mm , 1600mm , 1800mm , 1900mm , 2100mm hot selling solar vacuum tube