Actually, unregulated or Direct Drive lights would be what you're looking for if you need something to suck 'em 123s dry. While the TwinTask may or may not be able to do such a good job, some earlier threads have ppl asking about the best lights for such a task. Contenders (as far as I can remember) are the Inova X5t, Nighcutter for 2 cell (123) lights, and Arc LS, Tekna Splashlite for 1 cell (123)lights. I'm sure there are others that I've left out...