This is the second unit from DealExtreme that cannot stay on. If I push in the tailcap switch, it will only stay on while I hold it in. When I release and click immediately again, it switches mode to full, strobe, half just like normal. I am wondering if it is even worth sending back a second time or if there is something I can do to fix the tailcap switch. Any suggestions? I've tried different 2xAA batteries, but do not have a CR123a to try without the extension tube. I noticed another post with the same problem on the DX forum just a few days ago. I think maybe they got a bad batch or something.