During our stint at festivals and days out last year, I realised that I am really rather neurotic about losing my children in large crowds of people. It wasn't helped by the fact that my husband lost my five year old for about 60 seconds (which believe me seems like a very very long time when you can't see your child) at a theme park last year. And it seriously put a dampener on the rest of the day.
This child locator is really easy to use - you attach the teddy bear receiver (pictured) to your child's shoe or belt and if your child goes out of range (approximately 25 feet) the alert feature on the parent keychain starts chirping loudly. You then press a button on the keychain which makes the teddy bear that is strapped to your child start chirping, telling you of your child's whereabouts.
This child locator is perfect for someone like me, although Tom (husband) is less convinced. For me, it gives peace of mind in a crowded place with a wandering and very fast nearly three year old.
This child locator and alert retails at £24.99, which I think is very reasonable indeed.