In another thread I mentioned that you can use Pila 150s batteries in a Streamlight TL-3. Here are the instructions for the tweak.
1. Remove the tailcap, push the switch out
2. Then with a thin blade separate the plastic part #3 from the main switch #2. The place to insert the blade is thin and has those plastic pins you can see so move around if it won't go under easily.
2. Stick the part #3 in your parts drawer for future reference.
3. You're done
4. *might need* Twist the top coil on the spring tighter so that it fits better into the coil when compressed. On mine it stuck up slightly when compressed so I made it flush when compressed.
On my first attempt I sanded #3 until the Pilas would work #4. The problem was that the CR123s would not work. Apparently the difference in depth between the CR123s and Pilas doesn't compress the spring enough to touch the metal disk shown on #2. I only keep #3/#4 in a drawer if it is needed in the future but I don't see it being likely.
Also the Pelican M6 holster will fit this light if you take out the plastic bits in the bottom. You can also use Rip-offs for it. If you want the belt loop version of this holster not the clip on, substitute BL for CO. In this case a belt loop version would be BL-31.
I hope this helps you guys. If you've got any questions let me know.