battery swap-out & Question(s)

I have a Spectrum Brands l.e.d. night vision flashlite. It has a plastic battery holder w/3 AAA's. 2 face up and 1 is down. The unit has a hi/lo button.:beer:

what is the one down batt. doing?:wtf:

can other power sources be used other than 3 AAA?:angel:

are extions available?

What is the difference between 18650 and cr 123?:thinking:

can ....jayrod....be reached by email?:bowdown:

because 3 is an odd number you can' have 1 up, 1 down, 1 up. assuming it is a round holder. but if you pay attention to the wiring of the deal you will see that if you layed them out straight it would be connectiong positve to negative all the way through.
it is set up this way so raise the voltage from 1.5 up to 4.5
and his name is jayroB. its easier to reach him via pm. also 18650 batts are larger and have more capacity that cr123.

michael