Just received my uk unilite the other day, from bright guy, been playing around with it. It came with a 2.1 watts bulb, but I put in the eled replacement lamp, works great. For nightime walks, in the woods, with my dog, might use 2.1 bulb or 4 watt, with rechargible batteries. One trick I learned, is to use the clip, the light comes with, to attach it to shirt. Horizontially, and move the head, up and down, works perfect, like having a headlight attached to your shirt. I think for a work light it blows the regular uk 4AA out of the water. Good luck uk lovers.