I think OEM 4 and 5 energy saving bulbs kind, anyways I totally rejected them. I got reply from FANCO they claim it's the very first time such shipment has problems and just thank me for feedback. Both on the line with staff and reply email from a miss Claudia did not offer any apologies at all for the bad experience and inconveniences caused simply thank for feedback and will investigate. I was able to upload 7 photos attached to email sent to FANCO but did not know how to do it for this forum, it pops up a box asking URL http ..? Anyways don't want to embarrass them too much, like I said FANCO fans are excellent w excellent QC, quiet and strong breeze, even at no.1 fan it can be strong, we felt cold and has to turn it off after an hour to fall asleep!