Feit Electric 175-watt E39 Base high-lumen specialty lights provide maximum brightness in compact form. Use them to illuminate outdoor spaces, barns, streetlights, parking lots, or anywhere else you want more light. Use these bulbs only with ANSI ballast H39. Feit Electric H39KC-175/DX bulbs have a lifetime rating up to 24,000 hours, with an estimated annual energy cost of $21.08. Choose a dependable mercury vapor light bulb for your residential and commercial needs.