it looks like the same basic fan as my grandmas GE comercial HV 20" fan. the motor and the blades look the same. i did some research on it and i found it was made by the industrial grade fan division of lasko which if im not mistaken also owns airking? so thats pretty cool! it is very well crafted and very powerfull for such a late fan! late 90's i think?
It's "permanently" lubricated so no oil ports. Just have to watch the spin down. If it starts getting stiff you have to break down the motor and oil it. These are about the last of the great metal blade window fans. Air King was always an excellent brand. They are loud but they really move the air more than anything with a plastic blade. Of course in the deep south they are only good in March and November. Too much humidity.
