... -40mm polyurethane2. Vacuum tubes: 58*1800mm/47*1500mm3. Single side collector:10,15,20,25,30pcs vacuum tubes4. ... remote controlling based on customer's requirements.solar water heater project1.strong accommodation ability:choose proper obliquity collector ... and so on.3.high degree automatization:automatic electrical heater,automatic circulation and automatic protection4.free pollution,energy ...