Nickel-plated brass bases prevent corrosion while insuring a positive point-of-contact. Filaments, with "rough service" design, permit hours of reliable burning. T”represents tubular bulb shape; number after the dash is bulb diameter in eigths of an inch. • T-3.25: 1.06"H x 0.44"W • T-5: 1.49"H x 0.625"W