B&P Lamp Lampshade Diffuser, 13.5 In Diameter, Fits 15 And 16 Inch Openings Made of pure white acrylic material with a slip 1/4-27 and 1/8IP center hole. Removes light bulb glare Translucent Diffuser - for mounting on top of the shade or in the case of hanging lamp shades both the top and bottom of Drum style lamp shades. Directs light downward for accent or for improved reading light 13.5 In Diameter, Fits 13.5-16 Inch Openings(NOTE: Once adhesive paper is removed, no credit can be given if returned. Please make sure diffuser fits before removing paper.)