The ARMOR Condensing Water Heater is available in a total of 10 models, ranging from 399,000 to 4 million Btu/h. These models are constructed with superior-grade 316L stainless-steel, which reduces heat loss and provides up to 99% thermal efficiency and reliability for large commercial applications. This line features a 10:1 turndown ratio on models 399,000 through 999,000 and 5:1 turndown ratio on models 1,250,000 through 4,000,000 Btu/h.