... , CE and ISO9001 certificated.general specificationsMaterial: High Borosilicate 3.3 glass , aluminum fin , sealed rubber cirde .Outer tube dimension&thickness:Φ = 47 ... .7mm &=1.6mmLength: 800mm , 1200mm , 1500mm , 1600mm , 1800mm , 1900mm , 2100mm hot selling solar vacuum tube