Re: two or three brightness modes for DX C78
If you are using 14500 you can use the niteize multimode tail (same threads as 2 aa mag), and you will get high-med-low-sos-strobe, and the switch has a blinking locator beacon (if you want the beacon off you must unscrew the switch and screw it back in).
A single AA will not work though.. you have to use a 14500 with it.