... KEYMARK,SRCC,CE 3.Antifreezing -40 degree Canada Vacuumm tube heat pipe solar heating collector Specificationssolar collector; 1,Size ... .Solar energy collector:Size: 47mm,1500mm ;58mm/1800mm, tube quantity as your requirement.Copper pipe: material purple copper, ... spraying; thickness: 2.0mmHeat Pipe Evacuated TubeVacuum TubeThree high vacuum tube, ALN/ALN-SS/CU absorber coating, Dia: 58mm, Length ...