The new STM 225 dust-measuring instrument uses light-scattering technology to measure particulate-matter emissions of solid-fuel combustion systems. The instrument has none of the disadvantages of other well-known measuring principles, such as filter replacement, extensive preparation and postprocessing or measuring errors caused by shocks or vibration, says the company. Measured values are continuously displayed, and measurements can be interrupted at any time and resumed after a calibration phase of 15 s. STM 225 is a lightweight, portable instrument featuring easy, intuitive operation. It allows the chimney sweep to efficiently perform measurements and monitor systems for compliance with limit values. The heating-system engineer benefits from STM 225 in optimizing combustion systems in terms of minimum emissions. — Afriso-Euro-Index GmbH, Güglingen