Philips Advance HID ballasts are available to operate the wide variety of metal halide, high pressure sodium and low pressure sodium lamps available in today™s marketplace. Like fluorescent, HID lamps are gas discharge lamps. Light is produced by an arc discharge between two electrodes located at opposite ends of an arc tube within the lamp™s outer glass envelope. The ballast is the lamp™s power supply; its purpose is to provide proper starting and operating voltage and current to initiate and sustain this arc. Philips furnishes 120/208/240/277 Philips Advance Quadri-Volt core and coil ballasts to allow the stocking distributor to conveniently meet the replacement and retrofit needs of customers. In addition, we now offer 120/208/240/277/480V 5-TAP core and coil ballasts for the most popular applications. 5-TAP ballasts add the 480V input lead to the Quadri-Volt designs. A Quadri-Volt or 5-TAP core and coil, along with the appropriate capacitor, ignitor (where required), mounting bracket and hardware and installation instructions are packed in a space-saving shipping carton. These "kits" eliminate the need for distributors or end-users to stock loose components of single voltage ballasts for 120, 208, 240, 277 and even some 480V applications, though single voltage kits for 480V applications will also be available.