This is a great 1 AA flashlight. I use this flashlight EVERY day. I keep it in my pocket. It’s a great little light. It can use: 1 AA alkaline or 1 AA NiMH rechargeable or 1 AA Li-Ion battery. It has an out put of 190 lumen using Li-Ion battery and will run for 1 hour 15 minute runtime using the Li-Ion. But I hardly ever use a Li-Ion in it. 99% of the time I use a NiMH rechargeable battery like the Eneloop batteries. The difference in the lumens is noticeable but not a deal breaker. It makes a great EDC flashlight. With the NiMH batteries the light will last about an hour but you can recharge them and use them again so it has never mattered much to me. Also this little light is tough. It has stated in my pocket bumping up against my keys for the last 2-3 years and it still works fine. With a cost of under $10.00 it’s an absolute winner. It has 4 1/2 out of 5 stars on Amazon with over 1870 reviews!!