Check the listing for details. Nascom Overhead Door Contacts. Condition: New. Listed at 29.99 USD. The Nascom Overhead Door Contacts are a set of sensors specifically designed by the brand NASCOM for use in home surveillance systems. The model number N505AUTM/ST indicates the specific design of these contacts, which are crucial for detecting when a door is opened or closed, providing an extra layer of security in a smart home setup. These contacts are reliable and efficient in monitoring the security of one's home, making them an essential component for a comprehensive surveillance system.