In earlier times, before the invention of modern pin locks, most residential doors were secured by a 4 inch or so metallic key that kept family members in and unwelcome intruders out.
Sa mas maaga beses, bago ang pag-imbento ng modernong pin kandado, karamihan residential pinto ay sinigurado ng isang 4 pulgada o kaya metallic susi na itinatago miyembro ng pamilya sa at inaayawan intruders out.