A large French antique wrought iron entry door handle knocker from the 18th century. This impressive piece comes from Provence, France.
There is an old system: you have to put the bar in the door and fix it on the door back side with the removable piece. You can use it for a door of 1 3/4 inches to 2 inches (4,5 to 5cm) thick.

As found condition. See photos.

The first picture is an example of what it could look like on a door. 

Handle height: 7 1/8" (18cm)
handle width: 4 7/8" (12,5cm)
bar length: 3 3/4" (9,5cm)
Weight: 1,4 kg