1. Apply with high-strengh anodizd aliuminum alloy .
2. There is sealing element between vane and vane, vane and exterior frame.
3. Manual type can be adjusted in 6 levels between 0~90 degree , but the automatic one can stay at any angle.
4. NO.HFK-LM1 applies with gear rotating which is hided the inside of the frame with plastic cover to prevent the damage and dust.