Black Horse Shoe is fixed on the outer door of the house to keep evil spirits and evil eyes out of the house. It is considered as most auspicious item to remove bad luck and disease from the house. It is believed that Black horse Shoe work as a protective layer of the house, which protect the house from, diseases and bad luck.
It is recommended in our Vedas too that those who stick Black Horse Shoe on there outer wall or Door remains away from bad luck and diseases. The horseshoe is considered a lucky charm in the West as well as in India ! The shape of the horseshoe describes the ideal land configuration of Feng Shui, hence it is considered a favorable shape as per Feng Shui too.
In India, people have traditionally considered the horseshoe as a lucky charm and used it by affixing it above their main door on the outer side, for protection and good luck.