Aerovox D84W4021M01H 21UF 400 Volt, 320 Watt Pulse Start Capacitor. Commonly used for 320 Watt metal halide fixtures and works with M-132 bulbs with a constant wattage autotransformer circuit type ballast. The case is 1.77" diameter and 3.62" tall with a maximum temperature rating of 100oC (212oF). This case has two 8" long 18 gauge stranded copper wire leads with UL listed insulation rated for 150oC (302oF) and a resistor that dissipates charges to less than 50 Volts in 60 seconds when DE energized. This device is not protected against short circuit.