I tried one of the 4-watt lamps that is designed for the UK 4AA rechargeable, in a standard UK4AA with alkaline cells. The 4 watt lamp assembly is much more robust with an aluminum reflector/heat sink. The light is much brighter with a better hot spot and less artifacts. The beam quality approaches that of my Pelican StealthLite 4AA. Can anyone tell me what kind of lamp life I can expect with alkaline cells? Also, how about using NiMH batteries? Thanks for sharing.