I use some cheap chinese flashlight from tmart.com that uses a 18650 rechargeable battery. I also carry a personal fan that uses the same battery and recharges with a cellphone charger, so if needed I'll swap the batteries.
I used to use a Surefire and later a Streamlight but I got sick of replacing the expensive CR123A batteries.
I’ve got a Bostac BTZ-20 that is super bright. It’s rechargeable using a micro USB and I love it, except it’s a piece of junk. I have already replaced the battery once under warranty. Now I have a brand new battery and it will still just decide to stop working with no warning (indicator light is supposed to flash red when it gets low) and only lasts 3 or 4 walkarounds before needing to be charged again.... sooo I’m ready to invest in another one if anyone has a flashlight that they love.
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That excludes the 18650 battery and charger, but for the price those are great flashlights to have around the house