port-a-lock

A portable door lock designed to fit on any door. Most are small enough to be carried in a pocket or purse. There are many different designs on the market. The most common design consists of a simple metal plate that hooks onto the door knob’s strike plate, with a sliding piece that prevents the door from opening. Most interior doors, in American homes, do not feature built-in locks.

This little-known device saves lives in cases of domestic violence, and they should be given away in schools.