New Costco TechLites! $19.95 (3xAAA)

i was hoping for 300+ lumens, duracell branding does nothing for me

Brother is asking about these, I see people were mentioning 18500’s.

Can anyone confirm good operation on 18500 w/ sleeves?

3xAAA

I just wrap a protected 14450 li-ion in a bit of pipe insulation foam to keep it centered. Works fine.

Only lights that give issue in most cases are ones with 2 contacts on the end or cheap 5mm direct drive lights.
About 95% of 3aa lights work with 14500 or 18500 with spacers.
Some even work with 18650.