... Vacuum tube solar collector System 1.SOLAR KEYMARK,SRCC,CE 2.Antifreezing -40 degree 3.OEM provide Split pressurized Vacuum tube solar collector System1, ... connect each parts, each system have manual instruction.4.Use copper pipe for transfer hot, more high efficient, ... plastic spraying; thickness: 2.0mmHeat Pipe Evacuated TubeVacuum TubeThree high vacuum tube, ALN/ALN-SS/CU absorber coating, Dia ...