The Honeywell T7771A1005 is a temperature sensor with a 20K OHM NTC (Negative Temperature Coefficient) that is designed for use in HVAC systems. This product is an old stock item and is no longer being manufactured. It is ideal for use in industrial and commercial settings where precise temperature control is necessary. The Honeywell brand is known for its high-quality HVAC products, and this sensor is no exception.