... (10-30pcs vacuum tubes)Specifications:size: 47mm,1500mm,/58mm,1800mm, tube quantity calculate the tank capacity,copper pipe: material purple ... copper,glass tube: high borosilicate 3.3, thickness: 2.0mm,heat preservation ... Evacuated TubeVacuum TubeThree high vacuum tube, ALN/ALN-SS/CU absorber coating, Dia: 58mm, Length: 1800mm.Copper Heat PipeTU1, Silver ...