An opacity meter measure the level of smoke density in exhaust gases emitted from combustion processes. It is expressed as a percentage of light blocked by the particles in the exhaust gas. The exhaust gas is passed through a chamber between the light source and the detector. The opacity level is calculated based on the percentage of light blocked by smoke. it use for  better control over the combustion process and lower emissions. Measurement Range=0-to-100; Resolution=± 0.1 %; Repeatability=± 0.2%; Reproducibility=± 0.5%; Working angle=45-deg;for more visit Labtron.us