Which one? L
Check the data sheet for the LED or the sellers web site.
An LED is much like any other diode.http://en.wikipedia.org/wiki/Semiconductor_diode The characteristic forward voltage drop depends on what material it is made of, and is related to the color of light it emits.http://en.wikipedia.org/wiki/Light-emitting_diode#Colors_and_materials The maximum allowable current, or power handling ability, depends on the physical size and construction of the diode junction.http://en.wikipedia.org/wiki/Light-emitting_diode#Types
20mA @ 1.6V -standard red LED.Wanted to know something else? Ask a more specific question.