This small beige box mounted at a small distance from an exterior apartment building wall is an outdoor temperature sensor, manufactured by Heat-Timer Corporation of New Jersey. It senses the external temperature and controls the heating of a building, most commonly by cycling a boiler found in the basement of the building. NYC Department of Housing Preservation and Development mandates that all apartment buildings in the city provide heating when the outside temperature drops below given temperatures, and these sensors help buildings abide by those laws.
| Type | Sensor |
| Model | 3-in-1 Temperature Sensor in outdoor configuration |
| Primary Manufacturer | Heat-Timer Corporation |
| Owner/Administrator | Private Building |