Sierra-Omega-Kobold-Matheson 820August 24, 2012|Mass Flow Controllers, Sierra-Omega-Kobold-Matheson Home » Mass Flow Controllers » Sierra-Omega-Kobold-Matheson » Sierra-Omega-Kobold-Matheson 820 Coastal Instruments services a wide array of Sierra-Omega-Kobold-Matheson mass flow controller models. The Sierra-Omega-Kobold-Matheson 820 is one of the models we service.