Olight i3S EOS

A great, bright, ultralight mini flashlight that clips to the brim of your hat to function like a headlamp. All the light you need around camp at a fraction of the weight and cost.

This is a review of the Olight i3S EOS. I paid about $19 from a seller on Amazon. I am not affiliated with the manufacturer or seller in any way.

The i3S EOS is an LED flashlight that is incredibly tiny and feather-light but still full featured and surprisingly bright. High-efficiency CREE XP-G2 LED, powered by a single AAA battery. IPX8 waterproof (2 meters). Made of aircraft-grade aluminum, and comes with a reversible pocket/hat clip and a keychain attachment.

I took the keychain off of mine and it weighs only 0.4 oz with the hat clip. Add a lithium battery and the total weight is only 0.7 oz for all the light you typically need on the trail, which is one-third to one-fifth the weight of most lightweight headlamps. Dimensions are 2.7” long x 0.5” diameter:

With the reversible clip I can attach the flashlight to the brim of my hat and it works as well as a headlamp:


I also can attach it to the flick-lock on the trekking pole that’s holding up my shelter, creating a hands-free tent light. It would also attach easily to a hang loop, pack strap, endless possibilities:

The bottom of the flashlight is flat, which allows you to stand the flashlight upright on its end on a flat surface.

There is no on/off switch, you turn it on by tightening the screw-on head. Default first on position is the medium setting, but twisting the head on/off in fairly quick succession cycles the flashlight through three brightness levels (0.5/20/80 lumens), and alternating cycles include a strobe mode. After the flashlight has been off for more than a couple of seconds it resets and will start back at medium/default the next time it’s turned on.

Comes with a 5-year warranty from Olight. You can get it in red, blue, purple, gold or black. The light includes a cheapie battery and a couple of spare o-rings.It all comes in a little hard-shell case/gift box, which I could have done without, but whatever:

At a max output of 80 lumens this is not a major-duty light. It’s only intended to be a personal EDC light and/or alternative to a backpacking headlamp. And for these functions it delivers a great bang for the weight and for the buck. It’s similar in quality to companies like Fenix and ZebraLight, just at a much better price, and also better priced than name brand headlamps.

It does not have a red light mode, so is not the best choice for extended activity in the dark, but for around camp it’s great.