Beautifully bright and beautiful blue

The LEDs were packaged securely sealed by post-shipment to my house.
After a bit they shone even try!
Have tinkered with them, ie after one another two 1.5V batteries and the lamps, up to three parallel.
(Indicated value 2.9V operating voltage, they operate with constant [insofar batteries provide constant voltage ...] with 3V and up to now (after almost five weeks) has no LED made limp at ~ 5-10 hours of use per week.

The use with the supplied resistors I can not judge because I do not get the imaginary 12V portable, so for me are uninteresting. The resistors come but clean in appropriate numbers provided and could loslöten immediately! From the outside, no defects are detected and all the LEDs light!

For me ideal: 5Sterne