... 190m2/kw≥190m2/kwHailstone resistance25mm25mmStart up fast and collect solar energy fullyUnique super pure copper surface,allowing lower ... Long time warranty for 15 years.Absorptance of three high efficiency solar vacuum tube increased by 12%, and launch reduced ... heat loss less, warming faster. Efficient tube, the super absorbing, thermal efficiency is high, warming faster, in the same light ...