http://www.trutechtools.com/testo310Overview of the features and benefits of the Testo 310 combustion analyzer. The new Testo 310 is a new class of analyzer for Testo. Easy to configure, and use, the 310 is one of the best values in its price class. The Testo 310 measures CO, O2, draft, stack temperature and calculates, COaf or undiluted, efficiency, CO2, and more.