Rated to last 9 years (20000 hours) based on a usage of 6 hours per day; 4100 Kelvin cool white light; Uses 34 Watts; Contractor Case Pack: 30 bulbs per package; 2500 lumens/87 color rendering index; 48-inch T12 (1-1/2-inch diameter); Medium bi-pin base type (G13); Technical description: F34T12; Perfect for garage, basements, warehouses and industrial buildings