installed on exterior wall as the supply outlet , which is impervious to rainwater, and control the airflow,and also be the necessary establishment for each ventilative mode.

1) high strength aluminium alloy with smooth surface and strong corrosion-proof,
2) Manually or automatically control,
3) each index meet the requriement of GB/T3190-1996 standard.
4) low resistance, high effcinecy and intensity, can endure moist situations.
5) Easy installation and maintenance
6) Static painting as per requirement. (any color is available)