Aren't those Nano lights cute? But have you found yours not working right? Give it a couple wacks (not easy to do to such a small thing) and it's bright again? Open it up and find powdery corrosion film on your LR41's? Get rid of those Alkaline cells if you have any fondness for your Nano! Switch to Silver Oxide cells, these 392/SR41's are just the ticket to more reliable Nano operation and eliminating the possibility of corrosion, swelling, dead cells just when you finally need the Nano, or a messy, damaged Nano.
Silver Oxide cells have a much longer shelf and standby life, a greater capacity than their LR imitators, and a flatter discharge curve. They are worth the premium to keep that Nano clean and ready to go when finally you actually call upon it.

Silver Oxide cells provide greater capacity, flatter discharge, and longer shelf life, making them ideal fodder for your Streamlight Nano Key Chain light. Annoyed by the leakage causing intermittency in your Nano? That's part of using LR41's, Alkaline cells... how often have you twisted the Nano to find it flickering, and opened it to find corrosion products that need to be scraped and cleaned off? Switch to the slightly more expensive SR41 Silver Oxide cells.
The Streamlight Nano, like it's bigger brother the Steamlight Key-Mate are just the ticket for hooking on those sewn-in lanyards you find in your toiletries bag, laptop case utility area, or carry on utility bag helping you to fish out a useful light to find stuff in your case or under your airline or rail coach seat. It's frustrating when the light doesn't work, just dimly glows, or flickers... all that most often due to the leakage and corrosion of the Alkaline cells most easily found in Dollar Stores or hardware stores. Try SR41/392's.

These silver oxide batteries are dependable and convenient.

Purchased these on sale for my laser light. They work perfectly . These batteries are are a good value for the money even when not in sale.

I had previously purchased a laser ballpoint pen and had difficulty in finding the right battery replacement. I had used Battery Junction in the past and found the battery needed ordered it. I believe it was an excellent price.