17.5" Translucent Diffuser - Designed to fit the bottom of your 18" or 19" wide lampshade. (If you are using on top of the shade,please measure the top diameter.) DUAL USE - Perfect for mounting on top your table or floor lamp shade or it will fit the top or bottom of most hanging drum style lamp shades. No More Blinding Light - Everyone loves Mid-Century Drum style lampshade but they can sometimes cause the stark glare of staring straight into the light bulbs. A new diffuser will soften the light and diffuse the harsh glare from stylish drum shades. BETTER QUALITY LIGHT - A new diffuser will instantly improve the quality of the light, especially with energy efficient compact fluorescent or halogen light bulbs, which can often distract from the clean look of your lamp or light fixture. Softer light will cast light more evenly so it is easier on your eyes, improving reading and other tasks. ADD A FINISHED LOOK - they also add a finished look to many table lamps. When mounted underneath, a superior look and performance is achieved for Shallow Drum hanging fixtures. 25% THICKER - Home Concept Light Diffusers are a full 3mm thick (1/8) Other brands will try to skimp with 2.4mm thick acrylic. Be sure to insist on 3mm. Thicker acrylic will be more durable and will soften the light more thoroughly. Center Hole - Center hole is cut 10mm thick Matte Milky White Finish - Home Concept Diffusers are finished on both sides with matte Milky white acrylic. Some diffusers have a shiny side, but we use 100% matte acrylic, which does a better job of softening your light. Forget Peeling Paper - Unlike other brands, we protect your diffuser by individually bagging it, so you don't have to waste 2 hours peeling protective paper.