It looks like a headband and if a child that’s wearing one gets in trouble- parents and lifeguards will know.
If a child is submerged for 20 seconds, a light flashes on a tower. If a child is under for 30 seconds or more, an alarm goes off.
A YMCA in Connecticut paid $30,000 to install the system at their swimming pond. The makers of the technology say it’s especially helpful in murky water.