encryptor:
It says on the front of the package 5 volt, 30mA, 300mcd. Here is the link to this LED. I see in the reviews someone points out this is not really a 5V LED and results show to use 3.5V forward (supply) voltage.http://www.radioshack.com/product/index.jsp?productId=2102850
WOW what a ripoff, a blue LED should cost you no more than $0.20
Now attach a 220R or so resistor to one end and power it up with 5V. Use a meter to measure the voltage across the LED, this will be somewhere between 2.8 and 3.6V, use this to calculate the resistor value for your required current.