There are many apps that can help to protect your children from abduction. But kidnappers know about this and get rid of the child’s phone quickly. 
Converse inserted a device in the sole of their new kid’s footwear line that lets the kids call for help discreetly.

Powered by body heat, this SafeSole is always on. When your child taps out a special pattern with his foot, you and the police will instantly get the distress signal with his location.