Vintage Retro 60s 70s Perspex Light Shade Lampshade Plastic Rotaflex Hobnail. One small crack in the top of the shade (see pic) and small paint marks from lazy decorators!! When I got it I thought it was badly nicotine stained but I'm 99% sure it isn't. I've tried several cleaning methods on it and it's still the same and it doesn't have that slightly sticky feeling with nicotine. Its octagonal  and measures 6 1/2" x 6 1/2" approximately Please check the photos as they are part of the description.