1)heat pipe solar collector 2)vacuum tube:70X2100mm 3)with SOLAR KEYMARK AND SRCC certifcate Specifications: 1) ... Manifold and frame: Stainless steel or aluminual alloy2) vacuum tube with heat pipe inside;3) Manifold with copper coil inside ... : 0.8mm thickness, 1700mm length, or OEM.5) Vacuum tube:Two target or three target vacuum tube, 47*1500mm, 47*1800mm, 58*1800mm, 58*2000mm ...