Rheem’s RECTGH-S11iN (Natural Gas) or RECTGH-S11iP (Liquid Propane) IKONIC Super High Efficiency condensing tankless gas water heater delivers continuous, efficient hot water for your entire home. The integrated EcoNet App and Wi-Fi control allows to control, monitor and customize your hot water usage from your phone or other smart device. The RECTGH-S11i(N/P) dual heat exchanger technology maximizes efficiency and increases durability allowing you to enjoy efficient, continuous hot water in your entire home. The compact size, wall mount and industry leading installation clearance allows for installation in small spaces saving valuable floor space. Please note the end letter of model denotes gas fuel type. N: Natural Gas and P: Liquid Propane.