Is this a proprietary 18650?

I bought a bike headlight, the Enfitnix Navi800, because I liked the beam shape, replaceable battery, and on-board charging. But the battery, despite the "18650" written on the label, isn't like any I've seen so far. It has flat ends but the positive and negative terminals are both on the same end, with positive in the center.

Is there a name for this type of battery that I can search for? Or is it unique to Enfitnix?

Here's a thread found on a polish forum that has pictures of both the light and the battery: [lampka przód] krótka recenzja Enfitnix Navi800

It’s definitely proprietary which means you’re probably stuck with that battery since the housing and electrical connections are designed for it.

Yup, it's proprietary as explained on that Polish forum.

Reminds me of the Olight proprietary batts, I am not sure the polarity is the same…
18650 customized 3500mAh battery for Warrior Mini 2/ Perun/ Baton Pro/ S30RII/ S30RIII/ S2R/ R20 Javelot

Out of Stock… but might help you find something if you are in desperate need.

looks a lot like streamlight battery, for old strion model, and possibly other models too, i've seen cells like that on other brands as well, they are not common, but occasionally you come across one like that.

Thanks everybody. Fingers crossed that the company doesn't disappear before I ever need another battery

It would easy to make a little circuit board with the concentric positive and negative terminals, then rewrap after making a solder connection from the side of the case to the negative ring. The positive would just be a straight feed-thru that makes contact with the button top.

Here’s one from another source,

I think it would be worth cutting the wrapper off when/if you get to that point. Maybe you can scavenge the contacts and solder them onto a regular 18650. That’s all they have done.