Yes, the lithium 544 (6 volt) battery will work. You will need to take it's outer metal wrapper off. Inside are two 3 volt little barrel cells of 3 volts each. The diameter and length of the two cell stacked together is Exactly the same size as the 4-button alkalines (A-76 etc). A perfect fit! /ubbthreads/images/graemlins/cool.gif
Two reasons you might want to do this:
1. the capacity of the lithium cells is much greater than the 4 alkaline type 76/357/AG-13.
2. the light will work much better in extremely cold weather.
There are also NiMH (H40-1.2 volt) rechargeable button cells available.
