TOC combustion/IR with optional TN detector for water/soil samples. Can analyze TOC and inorganic carbon, TOC down to about 0.1 ppm and TN to about 0.2 ppm. We use for NPDES nitrogen analyses, stormwater, and industrial waste analysis. Very stable for long, overnight runs with full QC. Not too much maintenance, replace consumables and it runs well. Working inside can be a challenge, a lot of tight spaces to access. Would definitely recommend for labs that run these analyses.