Two combustion analyzers, models 310 and 320, can be used by HVAC techs for residential tuning and commercial applications. The 310 is a residential customer analyzer designed to measure flue gas, draft, ambient CO, and pressure, while the 320 is an instrument for residential and commercial boiler/burner tune-ups, service, and maintenance. The 310 features two high-range sensors to measure O2 and CO, and comes with a NOx filter standard. Readings are shown on a large, backlit multiline display. Other accessories include an integrated probe for flue-gas measurements of 32° to 752°F and a USB charger. The 320 features a vivid high-definition color graphic display. It can be used to measure O2, CO, CO2, combustion efficiency, excess air, draft, pressure, and differential temperature. It features two gas sensors and a variety of different probe choices which helps minimize the number of instruments necessary to take different measurements. It offers an integrated memory able to store up to 500 readings and can communicate with a variety of different hardware options, including PCs via Bluetooth, USB, and infrared printers managed by easyHeat software. Both analyzers are ready to measure in 30 seconds with an auto-zero function and an integrated magnetic back for hands-free operation. According to the company, the robust housing, ergonomic design, and rechargeable battery make both the 310 and 320 easy to use for combustion tuning and analysis. Both instruments have kit options that can include an infrared printer with 10-year legibility thermal paper.