https://www.theverge.com/2018/6/3/17418162/lynq-gadget-find-your-friends-off-the-grid

This Indiegogo campaign aims to help people who need to locate their friends and family in a pinch. Lynq is a little gadget that you can clip on your clothes or bag that tells you how far and in what direction other people are without any data connection needed.

The palm-sized device is as simple as can be: there’s only one button, and the sole purpose of Lynq is to show the distance and direction of other people in your group via a tiny circular screen. It uses long-range, low-power frequencies to connect to other Lynq devices and GPS for location, so no phones or Wi-Fi are needed. Lynq says it uses a custom antenna and users will have a closed, private network dedicated to the group.