Micher solar stock tank heater 1.Sample is available 2.lifetime: 15-20 ... .CE, CCC, SRCC, Solar Keymark, ISO14001 Micher Compact Pressurized solar stock tank heater Vacuum tube: Cercis SolarVacuum tube specification: Φ47×1 ... ULT=0.6˜0.7W(m²×°c) Compact pressurized solar stock tank heater