Since 1995, Sequoia Scientific, Inc. has been the global leader in technologies for submersible and field measurements of suspended particles, and particle size distributions. Sequoia invented the LISST series of aquatic science sensors in 1995. Since then, more than 40 different types of sensors have been developed, prototyped, or manufactured by Sequoia. Today, thousands of Sequoia instruments are in use, helping ocean and freshwater scientists and managers around the world better understand our oceans and the aquatic environment. All design and production takes place in our Bellevue, WA location. Our sales staff is located in Bellevue, WA and Mobile, AL. LISST was originally an acronym for our laser particle sizing sensors (Laser In Situ Scattering and Transmissometry). LISST now is ‘just’ a Sequoia trade name. Most of our instruments still use lasers in one way or the other to make measurements. A few use LED’s or acoustics. Sometimes two methodologies are used together. Several of our instruments measure the in-situ size and/or concentration of suspended particles – sediment grains, algae, flocs, oil droplets, air bubbles, aeolian sediment, drilling fluids etc. One model takes pretty particle pictures using holography. Others again measure water optical properties such as beam attenuation, Volume Scattering Function (VSF), and hyperspectral backscatter. The instruments are primarily used for ocean science and freshwater research and for environmental monitoring. However, some are used in select industries in a range of drilling fluid, hydropower, and general process control applications. How do you know if you need a LISST? Are you an oceanographer, limnologist, biogeochemist, geographer, geologist, soil scientist or coastal, environmental, consulting or drilling engineer? Or do you have an interest in (suspended) particle measurements or the optical properties of water? Or do you work in Industrial Process? Then we most likely have an instrument for you.