Air monitor, 1 meter optical path. Measures opacity, extinction coefficient, Particulate Matter, Particle Size, Concentration. Based on a 4” ABS pipe, the length can be adjusted from 4 feet to 12’. The endcaps hold the light source and sensor. This is the most sensitive particle measurement system for ambient air quality, indoor or outdoor. Mount it under the eaves of the house. 12V DC powered. Includes data logger and dashboard.