Random eBay part - wonder what it is

I order a couple of ESP8266’s
Then I opened the package there was 1 ESP8266 in the package but also a strange USB lead.
Looks like a USB to header connector and was wondering if anyone knows what it’s for.

Here’s a link to a picture of the cable.

Inside the strange loop thing are 3 pins so must be inserted into something.

I checked the sellers store and couldn’t find any pictures of any products like this one.

Any thoughts.

It looks like a USB charger cable for Fitbit Flex.