The Fail-Safe VR 2000 11" Round Series combines strength-gaining architecture with energy-saving technology. Architecturally-angled facets blend with its circular form to increase the ability of the lens to deflect blows and absorb impact. The extra thick injection-molded polycarbonate lens incorporates an optical design that obscures the lamp image and spreads light evenly. An emergency battery pack is also available on fluorescent fixtures. It is UL listed and CSA certified for wet locations. The durable, versatile 11" Round TC/TW is perfect for use in corridors, dormitories, public restrooms, rapid transit stations, loading docks and minimum security institutions.