The updated line of ARMOR Condensing Water Heaters 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, the company says. The line features a 10:1 turndown ratio on models 399,000 through 999,000 and a 5:1 turndown ratio on models 1,250,000 through 4,000,000 Btu/h.