The 1X65W replacement ballast for Coralife Aqualight Fixtures (except for Coralife Aqualight Retrofits) will run one 65W compact fluorescent lamps. NOTE: This ballast will not work in all Coralife Aqualight fixtures. Please check the model number on your ballast. This 1X65W ballast has Model: SPL-165R-JS written on it.