Mum-of-three Claire Bardner, 41, designed the wristband, which looks just like a digital watch, after her son Billy, now five, went missing at a football tournament.
It can store up to five telephone numbers, each accessed by pressing a button. When a button is pressed the number flashes up so an adult can contact the child's parents.
"It was an absolute nightmare when we lost Billy," Claire, 41, from Highgate, London, told the Evening Standard.
"But he now knows that if he can't find us he just has to find another mum or a shop assistant and they will be able to help him because he's got the phone numbers.
"After the incident with Billy it became a race against time.
"We started putting phone numbers in the children's pockets in case they got lost but the band has changed his behaviour.
"When parents see it they think it's a great idea, I'm very hopeful that 2012 will be the year that it'll take off.
Hopefully it will become a habit that a lot of parents will get into and save a lot of distress.
The wristbands, which come in three different designs and cost £14.99, are currently only available from Claire's website and from airline Aer Lingus.Simple yet brilliant idea, don't you think?