One thing, though, switching from a Cygo(tm) halo bulb ($15 from LBS) to the $3 batteryspace.com one, I find that the new one is a teeny bit loose, so I think I want to get a new gasket to keep the headset (or whatever you call it) water-tight. Meantime Cygo has offered to overhaul my light to see if there are any shorts to explain its bulb-eating ways. w/ no replacement, I think I'm better off feeding it $3 bulbs that don't quite fit until the sunny season comes (May, hopefully).