10 units of Vacuum Tubes for solar water heater, evacuated tubes for solar plastic shield for sensors 7) The direction of the

7) The direction of the wind with 360 degree

Soil Moisture Sensor

no obstacle in between

The use of Lithium battery is strongly suggested

10 units of Vacuum Tubes for solar water heater, evacuated tubes for solar plastic shield for sensors 7) The direction of theThis listing includes: 10 units of vacuum tubes (or evacuated tube) for solar,high performance. Length of tube: 500mm Application: they can used for the demo solar collector, demo solar water heater, or other DIY solar hot water heating system. Get the energy from the SUN. Remark: the tubes are fragile, we will ship to you via Express. (if tubes broken, we will ship to you again or refund to you, no worries) Description: Just like an automobile