Increase the square footage in your home and install your tankless water heater in an aesthetic and protective RB-900-1 recess box. For outdoor installation only the RB-900-1 allows a ventilation free install while essentially hiding the unit within your exterior wall. Compatible with the NRC83-OD / NRC98-OD / NR111-OD / NRC1111-OD / NCC1991-OD tankless water heater. Recess Box: An exterior encasement for your outdoor tankless water heater a recess box is built to provide adequate ventilation for your unit while protecting it from the elements and improving the finished look of the installation. Features: Hides heating unit within wall Outdoor installation only Protects system with a clean finished look Paintable finish Approved for zero clearance combustibles 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.