Normal solar tube is
1)Passing ISO9001
2)Specific Absorption:92%---96%
3)reliable quality,reaonable price

Three merits solar collector tube:

1. high strength,more durable for high temperature,high thermal efficiency.

2.Its mental layer at bottom is typically made of copper .Absorption layer and antireflective layer are compound of Nitrogen and aluminium ion,adding some component of stainless steel.

The structure of inner tube

color of inner tube: copper red

Comparing to the general tubes ,it maitains more efficient in heat preservation. Meanwhile, the chemical compound in the absorption layer is more pure than general,thus possessing the more efficient absorption rate