1. The voltage of 4 inch inner fans are: 110-120V, 60Hz or 220-240V, 50Hz.
2. Leather case: our company specially designed to reduce the noise of fans, but also to prevent air leakage, rust.
3. Foot frame: according to customer needs, there are a variety of styles to choose from.
4. Volute: there are two kinds of volute to choose from. In addition, we have plastic pipe fans and straight pipe fans.
5. Speed switch: we have two speed switch, three speed switch and stepless speed switch.