Small LED Driver, 1.7mA

SALE - closing these out, get them now before they are gone

Small 1.7mA constant current LED driver, designed to fit in N-Scale passenger cars, cabooses, etc. 
Input is 0 to 30 volts, AC, DC or DCC.   Board will give constant light starting around 4-5 volts
Will  keep a white LED alive for about 1 second on loss of DCC power

How many LEDs can I power?