The Reznor UDX175 Power Vented Gas Fired Unit Heater is a high performance heater designed for use in commercial and industrial applications. This unit features a vented design that allows for increased air flow and improved heat distribution. The Reznor UDX175 also features a built-in safety shut-off system that prevents the unit from operating if it becomes overloaded. The Reznor UDX175 Power Vented Gas Fired Unit Heater is a high performance heater designed for use in commercial and industrial applications. This unit features a vented design that allows for increased air flow and improved heat distribution. The Reznor UDX175 also features a built-in safety shut-off system that prevents the unit from operating if it becomes overloaded.