... high efficiency solar vacuum tube increased by 12%, and launch reduced by 30 to 40 percent, the super absorbing, heat loss less, ... provide products as request. Long time warranty for 15 years. Solar collector technology index Index nameChina national standards (GB/T ... 10mm range of not more than 1, the whole pipe, not more than 5, the stones shall not be a crack around, more than 1mm stone does not ...