150 Watt S55 High Pressure Sodium Quad Tap Ballast KitHPS Ballast Cross Reference: Advance Ballast 71A8172 001D Sylvania Ballast LU150 MULTI KIT Keystone HPS 150X Q Venture V90D1435K Sola E SZA00W150 High Intensity Discharge (HID) lamps require a ballast to apply starting voltage to the lamp and establish current flow an arc between the lamp electrodes. Without a ballast, the arc will extinguish or draw increasing current until some circuit element burns up. Ballasts provide system stability by limiting