Blade diameter:50in Air flow:43170m3/h Rotational speed :1440r/min Blades material :430ba stainless steel , thickness:1.2mm Shutter material :hot galvanized sheet, thickness:0.8mm, the middle piece is 1.5mm Frame :hot galvanized sheet, top and bottom frame is 1mm, left and right frame is0 .8mm. 1380*1380*450cm