I like SS-5039s, modified or not, because of the more interesting shape and surface. Smiling Shark SS-5039 1 x AAA size flashlight, modification notes, Now 3 x 7135 with modes, on a BLF Tiny 10 board. The main problem with them is that they don’t have a metal or screwed in pill, so for higher powers they need either a thick star or a fabricated pill that slides snugly into the head. At around two amps, the plastic reflector starts to melt.