I modded my 1 AA Browning 70 phantom to use 1 AA front, tapped into -+, ran wires around to rear, added two AA holders. So configuration could be one rear, or one rear and one front, or one front 2 rear. (Because changing batts adds up in a year, and if paid hourly when boss walks around corner and you are changing batts, it can irritate them.)
The one front and one rear is extremely balanced in my design.
So, I would guess this is a kick butt design--feeling like you aren't wearing anything on head--for those like my wife who freak out with anything on their head. While not ballsy enough for me, I give them two thumbs up on design. Looks incredibly well designed for what it is.
If priced under $20, I would pick it up, just to play with. I could see it useful for jogging, wife (Hey, could you wear this dear to clean a little better?), or as a loaner for some hard headed backyard mechanic working on my car/etc.