The high-efficiency K2 Firetube boiler from U.S. Boiler Company has a stainless steel vertical fire-tube heat exchanger and is available in six sizes, from 85 to 270 MBH. A combi version is also available at 155 MBH. It has an ergonomically angled touch-screen display, which interfaces with the Sage2.2 boiler control system and outdoor reset control. It comes with a three-in-one vent connection, top or bottom supply/return/gas connections, a split-voltage junction box with fused connection boards and a full-height side access panel. 717/397-4701; www.usboiler.net.