Israel’s Barkid has launched a smart bracelet that enables parents to supervise their children. The bracelet is worn by the child and an app installed in the adult’s cellphone keeps track of the child. Barkid’s product is not GPS-based, and therefore emits negligible radiation.
http://www.globes.co.il/en/article-israeli-co-barkid-helps-parents-track-children-1001181063