A door knocker is an item of door furniture that allows people outside a house or other dwelling or building to alert those inside to their presence. A door knocker has a part fixed to the door, and a part (usually metal) which is attached to the door by a hinge, and may be lifted and used to strike a plate fitted to the door, or the door itself, making a noise. The struck plate, if present, would be supplied and fitted with the knocker. Door knockers are often ornate, but may be no more than a simple fitting with a metal bob, or ring.
German professor Franz Sales Meyer distinguished three kinds of door knocker: the "ring", the "hammer", and an ornate category which could take the shape of an animal or another figure.

Device make: SONY
Device model: ILCE-7RM4
Color space: RGB
Color profile: sRGB IEC61966-2.1
Focal length: 120 mm
Metering mode: Pattern
F number: f/5
Exposure program: Normal
Exposure time: 1/160