I have been running a M*g 3 cell krypton bulb in my Tec 40 because it is brighter and has a better beam. It just blew about half an hour ago, and it can't have been run for more than 6 or 7 hours on four cells before it blew. I guess I'll have to buy a lot of 3 cell bulbs to run in this light because I don't care for the original bulb (very yellow, very uneven beam, and dimmer than the 3 cell bulbs)! /ubbthreads/images/graemlins/icon23.gif /ubbthreads/images/graemlins/frown.gif /ubbthreads/images/graemlins/broke.gif