Light Bulb:(1)13w Quad Tube GX23-2 CFL 7" new constructionfluorescenthousing. Ideal for commercial and residential applications. Can be covered with insulation. Integral 120v ballast for one 13w CFL lamp. Air-Tite housing prevents airflow between attic and living areas. Fits 2" x 8" joistconstruction. Use with 7"trims.