Suited for both indoor and outdoor applications, Ultra Series RUCS/RUS75 and RUCS/RUS65 feature BTU ratings of 160,000 and 130,000, respectively. Condensing tankless units offer concentric/dual-pipe venting options and status monitor control while delivering endless supply of hot water. Heaters are suited for installations that do not require high BTUs, such as smaller single-family homes and multifamily residential projects.