Bosie-Boo Child Out of Distance Monitor

Here's a half-way step between reins and letting your child run completely free: the Child Out of Distance Monitor.

The child wears the smaller unit, and the parent sets a distance he or she feels safe with, from 5 to 50 metres. An alarm then goes off if the child wanders out of this radius.

That all sounds fine, except that it doesn't actually tell you where your child has gone - and with a fifty metre radius, I can imagine that might be a slight problem.