contact me:himin24 at hotmail dot com All glass evacuated tubes are the key component of solar collectors.The evacuated tube is similar to a conventional Dewar flask and consists of two borosilicate glass tubes,a glass with high chemical and thermal shock resistance. The outer side of the inner tube is coated with a sputtered solar ive surface. This coated inner tube is closed at one end and sealed at the other end to the outer tube.The annular space between the outertube and inner tube is evacuated to virtually eliminate heat loss by conduction and convection. Himin evacuated collector tubes are produced according to two new patents the Sydney University exclusively licensed to our company. The characteristics: 1. High solar-thermal conversion and low heat loss 2. Stable advanced coating up to 380 degree centigrade 3. Long time warranty to 15 years 4. High level vacuum ensure operation under cold weather