While candlepower and lumens are more popular measures of light output, neither really capture the actual useful light at distance. There are no commonly available instruments to measure either candlepower or lumens. Instead, formulas are used to estimate the “power” emitted by the light at the source of the light. The formulas can include size of reflector, bulb wattage, mounting position, shape of the reflector, etc. Formulas are specific to manufacturers and there are no universal standards. While an inch or meter is the same any where in the world, one company’s candlepower formula can be dramatically different from another company’s formula. Thus, some lights with multi-million candlepower may under-perform another company’s light with sub-million candlepower rating. Lumens have taken the place of candlepower for HID and LED light sources and are calculated using proprietary formulas as well. There are a few labs in the world (GE has one) that claim to possess the spherical chamber and instruments necessary to effectively capture and measure lumens. However, in most cases, the manufacturers of the lights rely on the manufacturers of the lamp assemblies to specify lumen output.
z – as far as I can tell – very bright.