Replaces your regular door locks, to keep your kids from falling out of the car.
My mother should have had a set for our car back when my Brother was 2-3, He opened the door on an off ramp and fell out one day. Other than scrapes and cuts, he survived, but it may explain a few things about him.
You push and twist to lock, use you key to open it up. Instructions included.
Fits 1971-1976 Chevy cars, has 2 different base pieces for the different models. Chevelle, Nova, Camaro, Impala and Caprice. May fit other GM cars also but this was all that I could find for them.
From a Chevy Dealership That closed up.