The FS4 vertical stainless steel single wall firestop adds another level of protection to your home. The FS firestop piece continues the durable easy to install stainless steel design seen throughout the Noritz N-Vent series. As part of the N-Vent series this product is approved for tankless and boiler stainless steel exhaust installations enabling you to know you ve made the right choice in both form and function. Firestop: Noritz leaves nothing out when it comes to you and your homes safety. The FS3 firestop enables your opening to maintain it s in place fire-resistance rating while doing its job as an integral part of the fire resistance system. In addition the piece is part of the N-Vent series so it s approved for tankless and boiler stainless steel exhaust installations enabling you to know you ve made the right choice in both form and function. Features: Helps maintain fire resistance ratings through openings High temperature rated stainless steel Quick snap connection Adjustable venting UL Listed / Special Gas Vent System Category II III IV Introducing the latest advancements in tankless water heater technology for your home Noritz tankless hot water heaters are both eco-friendly and energy efficient providing savings up to 40% in utility costs. Their gas water heaters warm water on demand which means you ll always have hot water and it will never run out.