Regina - yup, that's the bottle. It does have a standard wide mouth sized cap, so the Firefly fits on just fine. You can have drinkable liquid in it, but yes, it is a screw cap so drinking on the go would be somewhat out of the question. My coummute is short so I'm not really worried about having water for it.

SadieKate - no, I don't think that it is as bright as a DLG (but we are talking 70$ less dough too....), but it does cast a pretty nice looking glow on the ground and is nice and bright from the sides. I'll have to see if I can get some better photos. It takes 3 AAA batteries and I have NIHM rechargables - they are just like rechargable AA's (they use the same charger as the AA's even). If the battery life is anything like any of the other LED devices that I have I expect they will last a long time between charges and I have enough that I can have a set charged and waiting when the first set runs out.