Sequoia Scientific has been building instruments for making measurements in the marine environment since 1995. The LISST-200X and its predecessors (the LISST-100 and LISST-100X) has become the go to tool for measuring particle size and concentration in the ocean. The LISST-Holo is a holographic particle imaging system that can produce images of particles as well as obtain size distributions. The LISST-VSF and LISST-Stokes are specialized instrument made specifically for the ocean optics community. The FlowControl is our newest product and is used with other optical instruments such as WetLabs AC-S to provide the ability to automatically switch between filtered and unfiltered source water and thus greatly improve the accuracy of data.  HydroLight is widely used software for computing underwater radiance distributions and related quantities as needed for optical oceanography and ocean-color remote sensing.  EcoLight-S is a subroutine package for computing underwater irradiances for use within ecosystem and iterative inverse models, where extremely fast run times are required.