The Johnson Controls Thermostat Direct Acting Dual T4002201 T-4002-201 is a rectangular, wall-mounted pneumatic thermostat designed for use with central furnace and central air conditioner systems. It features a dial control style and adjustable thermostat settings, making it easy to adjust the temperature in your space. With a one-year manufacturer warranty, this thermostat offers reliable performance and is compatible with various brands and models. The gray color and simple design make it a versatile option for any HVAC system.