B8520 AI Internal Ballast Fits Allis-Chalmers Fits Bobcat Fits Case-IH Ca 12 & 2One New Aftermarket Replacement HID Internal Ballast Universal Fit for Agricultural and Construction Equipment Work Lights This aftermarket replacement HID (High Intensity Discharge) internal ballast is a direct replacement for the ballast housed inside WL8520 E and WL8520 F work lights. The ballast regulates electrical current and provides the high voltage needed to ignite and sustain the HID lamp, preventing flickering, dimming, and premature bulb