Progress Lighting P7019-30WB White Acrylic Diffuser and White Baked Enamel Housing For Standard 120 Volt Normal Power Factor Ballast, White White Finish White acrylic diffuser Size: 4-Inch Width, 1-5/8-Inch Height Extends 18-3/8-Inch Uses (1) 15-Watt F15T8 bulb (included). Some Assembly Required Progress Lighting has over 5,000 lighting fixtures offered in our catalog, the largest single source for residential and commercial lighting