SuigenerisYou should be careful with those batteries as they are unprotected and if you discharge them completely you risk fire. Explosion... Them work great for ecigs or flashlights w/protection. Don't blow your head off or someone else's.. Get a nice Panasonic 18650 protected battery be safe
SuigenerisDon't be worried about using unprotected batteries in this light as it's DESIGNED to use unprotected batteries: "BATTERY OVER-DISCHARGE PROTECTION CIRCUIT FOR UNPROTECTED BATTERIES". The standby current is also super super low so even if you leave your batteries in your flashlight for long periods of time unused that won't drain them either.
EDIT - I'm using these batteries and charger and it works exceptionally well for me, fwiw. https://www.amazon.com/gp/product/B00QKD4V4C/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 https://www.amazon.com/gp/product/B00KW2ZDHQ/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1