vacuum tube Solar Energy Water Heater 1,high heating efficiency 2, easyly installation 3. energy-saves vacuum tube Solar Energy Water HeaterSpecification:1) Vacuum tubes: Φ47 x ... 1,500mm, Φ58 x 1,800mm, Φ70 x 2,100mm2) Vacuum tube ... more information ,Packing:Standard export carton and foam vacuum tube Solar Energy Water Heater