GE plant and aquarium fluorescent bulbs highlight the natural beauty and color of aquatic life and plants. They are specially designed to promote growth and flowering of plants and aquatic vegetation. Contains a combination of phosphors that produce light rich in reds and bluesSpecially designed to promote growth and flowering of plants and aquatic vegetationUse to highlight the natural beauty and color of aquatic life and plants1.0 inch diameter T8 with medium bi-pin (g13) base18 inch longLasts 3.4 years based on 6 hours per day usage