... standards;low cost * High Frequency sine-wave output, the lamp electrodes impact smaller , low lumen decay , free of flicker ... , compared to low frequency square wave output ballast, lamp lifetime span last more than 1.4 times * ... .5 * Lighting Voltage: 3-4KV * Efficiency : >=87% * Lamp Current Crest Ration: <1.7 * Tube Voltage: 85-120V * ... : 76*69*32 mm 20W High Frequency Metal Halide Integrated Bulbs