Bicycle Lights

What is a LUMEN?

A lumen is a measurement of the amount of light that is contained in a certain area. The
technical definition of a lumen is one candela multiplied by one steradian. A much
simpler definition of a lumen would be that one lumen is equivalent to the amount of
light put out by one birthday candle when you are standing one foot away from it. If a
light bulb puts out 100 lumens, imagine standing one foot away from a cake with one
hundred birthday candles on it.