Sierra-Omega-Kobold-Matheson 840August 24, 2012|Mass Flow Controllers, Sierra-Omega-Kobold-Matheson Home » Mass Flow Controllers » Sierra-Omega-Kobold-Matheson » Sierra-Omega-Kobold-Matheson 840 Coastal Instruments services a wide range of Sierra-Omega-Kobold-Matheson mass flow controller models. The Sierra-Omega-Kobold-Matheson 840 is one of the products we service.