... ±0.5mm &=1.6mm,dia.=58±0.5mm &=1.6mm, Pipe Length1500mm, 1600mm, 1700mm, 1800mm, 1900mm, 2000mmAbsorptive Coating PropertyStructureCu/SS-ALN ... ²Average Heat Loss CoefficientUlt=0.4~0.6W/( m².°C)Pressure-Endure Ability0.6MpaHail-Endure Ability30mmLifetime15yearsSolar water heater vacuum tubeNormal solar collector tube;its mental ...