Jesco Lighting SP5-21/64-W Sleek Plus Classic Non-Grounded 21-Watt T5 Light Fixture, 6400K Color, White Finish Fluorescent fixtures linkable up to 10 units, and furnished with replaceable lamps, direct connectors, mounting clips, and ribbed acrylic lamp covers Housing made of extruded aluminum, with white enamel painted finish Fixture features a built-in instant-start, no flickering, silent electronic ballast rated AC120V 50-60Hz Ribbed acrylic diffuser lamp cover fits securely on the housing of the fixture with no light leaks, warping or deformed lens T5 lamps (included with fixtures) are energy efficient, long life with a 20,000 hours rating