20"26"30" Industrial Stand Fans 1. metal material,large wind 2.djustable ... grill,easily clean 20"26"30"industrial adjustmental stand fans: model standard flow rate speed voltage power noise mm ... of the aerodynamic testing ,air flow,and noise of small,stable and economic energy3.Three high,medium and low ... different users.4.It is for the floor strong fans,it can emit polluted indoor air,moisture,smoke, ...