Certified optical transmission monitor to measure the opacity or dust concentration of sample gas. Suitable for plants which require the monitoring of dust missions by law. Please note that this product was discontinued on December 31st, 2016. Further details are given in the end of life notification. Repair at manufacturer site, remote and field service as well as spare parts are available until end of 2025.As sucessor product, DURAG offers the D-R 290 2G which is mechanically compatible.