The lampshades are measured in cm diameter - this is the full measurement across the lampshade.
The lampshades come with a standard 40 mm European fitting and also a plastic 25 mm converter plug.
The bulb fitting is about 4 cm from the outside lampshade ring (top if ceiling fitting and bottom if a lamp option).
Candle Clip Shades:
These fit 40w regular candle bulbs, 25w halogen candle bulbs or 7/9w low energy candle bulbs
Drum lampshades are lined with flame retardant PVC which has passed glow wire tests carried out by the lighting association.
Low energy light bulbs are recommended ( 60 watts or less or 40 watts for small/ candle clip shades).