Perfecto Reflector Fluorescent Light Strip 20in Oa Features include: injection molded--made of high impact polystyrene, good for fresh or saltwater, fits all brand of tanks, vented for heat dissipation, water resistant rubber boot protects switch from corrosion. Comes with one 18" T-8 (1"diameter) lamp. Fixture has a 90 day warranty against defects in materials and workmanship. Fixture is 20" l x 4" w x 2.75" high.