Knocker n. : One who, or that which, knocks; specifically, an instrument, or kind of hammer, fastened to a door, to be used in seeking for admittance.

Example:
Looking for door Knocker that has a seperation of 4 5/16" from one screw to the next?

Taxonomy
brass knocker, dictionary, Encyclopedia, online dictionary, knock, thesaurus browser, Free Online Dictionary, Translations, hinge, synonyms, antonyms, big shot, English dictionary, free online English dictionary, metal ring, Vulgar Slang, metal object, fish.

Defination from the web:
knocker in the Online Dictionary. Meaning of knocker. Pronunciation of knocker. Translations of knocker. knocker synonyms, knocker antonyms. ... Now, it is a fact, that there was nothing at all particular about the knocker on the door, except that it was very large. ...