Sequoia Scientific


Submersible Particle Size Analyzer

Particle and sediment sensor holding calibration FOR LIFE!

The LISST-200X is Sequoia’s workhorse. It is a self-contained submersible laser diffraction particle size analyzer, designed for measuring suspended particle size and concentration in the aquatic environment – oceans, rivers, lakes, streams. A fast response temperature sensor and a high-resolution depth sensor makes it suitable for profiling or towing. With Sequoia’s optional BioBlock accessory it can be deployed for months on moorings or landers for long-term studies. For the system integrator, the LISST-200X can power and accept inputs from up to three external analog sensors. Data can be output in real time. The LISST-200X is typically used for sediment, (harmful) algae, oil-spill, ocean optics, visibility, dredging, aquaculture, environmental and laboratory applications.


  • Small angle forward scattering laser diffraction technology
  • Measures particle size, concentration, beam attenuation, VSF, depth, temperature
  • Self-contained with internal programmable datalogger for autonomous data collection
  • Externally powered (short- and long-term deployment battery packs included)
  • USB connection to PC for programming, offloading and real-time size distribution displays
  • Integrated depth and fast response temperature sensors
  • Power and integrate up to three external analog sensors
  • Analog output of mean particle size and total volume concentration for CTD integration
  • Real-time output of complete Particle Size Distribution (for s/n 2131 and higher)
  • Wide range of accessories available (see Accessories tab)



  • Small-angle forward scattering
  • 32-ring custom photodiode Ring Detector + 4 large angle detectors
  • 25 mm optical path

Parameters measured

  • Particle Size Distribution from 1.0-500 µm in 36 size ranges
  • Depth (600 m max depth @ 0.01 m resolution; 200 m with BioBlock installed)
  • Temperature @ 0.01 deg C resolution
  • Optical transmission @ 0.1% resolution
  • Volume Concentration @ 0.1 µl/l resolution
  • Volume Scattering Function from 0.039 to 13.8 degrees in water
  • Analog output of Mean Size and Volume Concentration

Operating Concentration range

  • Optical transmission from 0.3-0.99 (30-99%)
  • Concentration from ~ 0.5-700 mg/l (grain-size dependent)

Mechanical and electrical

  • Dimensions 10.03 cm (3.95”) Ø x 63.9 cm (25.2”) L
  • Weight: 5.4 kg (11.9 lbs) in air, 1.7 kg (3.8 lbs) in water
  • Operating depth: 600 meters max (200 meters for optional BioBlock accessory)
  • External power input: 12 VDC nominal, 9-24 VDC
  • Sampling rate: Up to 1 Hz
  • Current drain at 12 V: 75 mA when Sampling (100 mA for serial number 2130 and earlier)
  • Data storage: 1 GB (~12,000,000 size distributions)

LISST-200x dimensions


Large external battery housing 

  • Dimensions 10.03 cm (3.95”) Ø x 53.4 cm (21.0”) L
  • Weight (including 16 Alkaline D cells): 5.2 kg (11.9 lbs) in air, 1.5 kg (3.3 lbs) in water
  • Small external battery housing
  • Dimensions 6.35 cm (2.5″) Ø x 30.2 cm (11.9″) L
  • LISST-200X Battery Dimensions



LISST-200X Item # and Description

Item #DescriptionThumbnail
SEQ-FP-L200XLISST-200X Sediment Size Distribution Sensor
1 um -500 um size range
600 m depth rating
1 GB of memory
Integrated depth and temperature sensor

Large and Small Submersible External Battery Housings with short cable
Charger and rechargeable batteries for Small Submersible External Battery Housing
2 m communications cable with built-in USB
Small Volume Test Chamber
Pelican shipping container with custom foam cushioning
Windows software for programming, data offload and data analysis
Must be purchased together with new instrument.
No picture
One-time service of instrument within 36 months after delivery.
Includes one-way return shipping from Sequoia, all evaluation, diagnosis, testing and calibration.
Parts and labor for repairs not included.
Must be purchased together with new instrument.
NOTE: End-user responsible for return shipment DDP to Sequoia.
No picture

LISST-200X Upgrade Options

Item #DescriptionThumbnail
SEQ-AC-L200X-UPGLISST-200X Upgrade to Support HAB & Black Sensor Suite - Electronics upgrade and testing of existing 200X to support external sensors (sensors and mounting hardware sold separately)No picture.
SEQ-AC-SNR-MNTBlack/HAB mounting and cable hardware (w/o sensors)
Mounting and cable hardware but no sensors (requires an upgraded LISST- 200X and the correct Turner Designs sensors).
SEQ-AC-BLK-PKGLISST-Black Sensor Package
Black complete sensor package (includes mounting hardware/cables and Turner Designs sensors but not upgraded LISST-200X).
HAB complete sensor package (includes mounting hardware/cables and Turner Designs sensors but not upgraded LISST-200X).

LISST-200X/-Black/-HAB Accessories *NOT INCLUDED* with instruments

Item #DescriptionThumbnail
SEQ-AC-L200X-PRMOptical Path Reduction Module for LISST-200X
Extends concentration range by factor of five by reducing the optical path from 25mm to 5mm. Includes fused quartz cylinder and mounting hardware.
NOTE: The standard Background Test Chamber for LISST-200X will not work with the PRM in place. It is highly recommended to use the Large Volume Test Chamber for obtaining a background with the PRM installed.
SEQ-AC-L200X-CHLGLarge Volume Test Chamber for LISST-200X
Clear acrylic chamber with O-ring seal and drain. Used for obtaining clean water backgrounds with Path Reduction module installed.
SEQ-AC-L200X-SCOOPScoop for LISST-200X Optics
For applications in rivers and other regions where the LISST-200X is pointed into the flow. Ensures a diverted flow of water through the optical path of the LISST-200X. Includes s/s bolts and nuts.
SEQ-AC-L200X-FRMMounting Frame for LISST-200X & Small Battery
316 s/s frame. Includes:
bridle and set of two small battery housing clamps
SEQ-AC-L200X-FRM-CLPSmall Battery Housing Clamps (set of two clamps)
NOTE: Clamps are included with the LISST-200X frame.
2 m cable with Impulse 6-pin MCIL-6-FS connectors on each end, wired pin to pin
Allows connection of LISST-200X to Sea Bird CTD with Impulse MCBH connectors.
No picture.
2 m cable with Impulse 6-pin MCIL-6-FS connector on one end, and Impulse AG206-FS connector on opposite end, wired pin to pin.
Allows connection of LISST-200X to Sea Bird CTD with AG connectors.
SEQ-AC-L200X-CHFPFull Path Flow Through Chamber for LISST-200X
Flow through chamber that allows pumped water to pass through the optics of the LISST-200X. Simple to install. Includes barb fittings for 1/2" ID tubing. Compatible with standard 1/2" NPT fittings.
SEQ-AC-L200X-DPSRTowed Underwater Depressor
Designed to secure the LISST-200X instrument into a tow-body configuration, allowing the ability to be deployed from all types of watercraft working at speed. Includes tow-body and installation brackets for securing. Dry Weight 25 lbs.
SEQ-AC-L200X-BIOLISST-200X BioBlock mechanical anti-fouling wiper and shutter.
Includes mounting clamps (SEQ-AC-L200X-BIO-CLP).
NOTE: BioBlock depth rating is 200 m.
SEQ-AC-L200X-BIO-CLPLISST-200X BioBlock mounting clamps (included w/ LISST-200X BioBlock)
SEQ-AC-L200X-BC2LISST-200X 2-metre cable to small/large battery housing

LISST-200X/-Black/-HAB Accessories *INCLUDED* w/ instruments

Item #DescriptionThumbnail
SEQ-AC-L200X-LEBLarge External Battery Housing for LISST-200X
Anodized aluminum housing for external battery pack with underwater connectors for mating with LISST-200X. Includes 16 non-rechargeable alkaline D cells installed. Suitable for longer deployments. 600 m depth rating.
*Included as part of LISST-200X standard package.* Does not include cable SEQ-AC-L200X-BCS to connect to LISST-200X.
NOTE: Ships in a corrugated cardboard box.
The price does *NOT* include shipping container (e.g. SEQ-AC-L200X-SC).
SEQ-AC-L200X-SEBSmall External Battery Housing for LISST-200X
Plastic housing for external battery pack containing 2 rechargeable NiMH D cells with underwater connectors for mating with LISST-200X. Includes 4 rechargeable NiMH D cells and Battery Charger. 600 m depth rating.
*Included as part of LISST-200X standard package.* Does not include cable SEQ-AC-L200X-BCS to connect to LISST-200X
NOTE: Ships in a corrugated cardboard box.
The price does *NOT* include shipping container (e.g. SEQ-AC-L200X-SC).
SEQ-AC-L200X-SBATLISST-200X Rechargeable Batteries for Small Battery Pack
NiMH D cells, Qty. 4
*Included as part of LISST-200X standard package*
SEQ-AC-L200X-SCHGRLISST-200X Battery Charger for NiMH D Batteries
*Included as part of LISST-200X standard package*
SEQ-AC-L200X-BCSShort Cable for connecting Small or Large LISST-200X battery housing to LISST-200X
0.5 m long, 5-pin Male to 5-pin Female
*Included as part of LISST-200X standard package*
SEQ-AC-L200X-CHZSBackground Test Chamber for LISST-200X
Test chamber which holds small volume of water around optics while clean water background is obtained.
*Included as part of LISST-200X standard package*
SEQ-AC-L200X-CBL02Integrated Communication and External Power Cables for LISST-200X/-100X/-STX/-Deep
2 m length. Includes black-jacketed cable spliced to the single communications/power connector. Includes built-in USB adapter that allows the instruments to be powered from PC USB port.
*Included as part of LISST-200X standard package.*
SEQ-AC-L200X-SCReplacement Shipping Case for LISST-200X
Plastic shipping case with custom cut foam for LISST-200X. Also has cut outs for small and large batteries, spare batteries, battery charger, and short cables.
Picture on the way!

LISST-200X / -Black / - HAB custom length cables

NOTE: To order any cable, order qty 1 base item #, and qty xx cable item #, where xx is cable length in integer m.
E.g., to order a 45 m cable for powering a LISST-Black via a power brick, order:
Base Item #Topside ConnectionCable Design
SEQ-AC-LISST-CBL5FUUSB for Data and External Power. NOTE: Only works for LISST-200X, NOT with LISST-Black / LISST-HAB. Use SEQ-AC-LISST-CBL5FM or SEQ-AC-LISST-CBL5FUP instead.
SEQ-AC-LISST-CBL5FMMolex adapter w/ USB, Molex adapter w/ RS-232 + power
SEQ-AC-LISST-CBL5FUPUSB for Data, Power Jack (incl. power brick) for external power
SEQ-AC-LISST-PT5FBare wires ONLY - see drawing!
SEQ-AC-LISST-CBL6FMMolex w/ wires
SEQ-AC-LISST-PT6FBare wires ONLY - see drawing!
Cable Item #DescriptionThumbnail
SEQ-AC-LISST-CBLYYellow submersible cable. Reinforced.


What does the LISST-200X measure?

The LISST-200X measures the size and concentration of particles suspended in water.  It can measure particles from 1 to 500 microns.

It also measures the water temperature, depth, and optical transmission.

How does the LISST-200X differ from the LISST-100X?

The LISST-200X is very similar to the LISST-100X, but improved in almost every way.  It makes the same particle size and concentration measurements.  However, it is smaller, measures a wider range of sizes and can measure higher concentrations.  It also can output Mean Size and Total Concentration as analog voltages that can be monitored in real time, such as through a CTD, while the detailed size distribution and concentration information is stored on-board the instrument. For full details see the Feature Comparison: LISST-200X vs. LISST-100x


How deep can the LISST-200X operate?

The LISST-200X has a maximum depth rating of 600 meters which is twice the depth of the LISST-100X.  For deeper applications you can use the LISST-Deep instrument which is rated to 3000 meters.

Can I add the LISST-200X to my CTD?

The LISST-200X has been designed to plug right into existing CTD systems.  It has a dedicated 6-pin connector that is pin-to-pin compatible with SeaBird CTDs.  The LISST-200X will receive power from the CTD and output the Mean Size and Total Volume Concentration as analog voltages that can be viewed in real-time through the CTD cable.  The detailed size distribution information is stored on-board the instrument for later downloading.

How fast can I tow or profile the LISST-200X?

The LISST-200X uses laser diffraction to measure the size and concentration of particles.  This scattering occurs at the speed of light.  The speed of the water and particles passing through the laser beam does not change measurement.  As long as bubbles not being generated or shear forces are breaking up particles of interest speed does not effect the measurement.

How long does the Small External Battery last?

The LISST-200X Small External battery uses two rechargeable NiMH D-cells.  The LISST-200X can sample continuously at 1 Hz for 6 to 8 hours before the batteries will need to be replaced or charged.  We provide 4 batteries with the LISST-200X so that two batteries can be charged while two are being used.  An Excel spreadsheet is available to estimate the life of the battery when using different sampling conditions such as a burst every 15 minutes.

Can I use the LISST-200X as a laboratory particle size analyzer?

The LISST-200X is designed to be used submerged in water as its primary function.  However, like with the LISST-100X, we offer small chambers with a built-in mixer or flow through capability that allows you to use the LISST-200X in the lab as a particle size analyzer.

If the primary function of the instrument is to be laboratory instrument you might consider the LISST-Portable|XR particle size analyzer which is specifically designed to be used for laboratory particle sizing.

Does the LISST-200X process and output data in real-time?

Yes. The LISST-200X s/n 2131 and higher can process and output the complete particle size distribution on the RS-232 serial connector at 0.5 Hz. This requires firmware version 2.102 or higher and LISST-200X software version 1.14 or higher. Contact Sequoia support for more information.

What languages are supported?

As of October 2021, the LISST-200X software supports English and Danish. Contact us to enquire about the possibilities for getting the software in your language.

How does the LISST-200X compare to the discontinued LISST-100X?

It’s a lot better! Have a look at this comparison sheet.

Can I rent the LISST-200X?

Yes. Sequoia has a rental unit available. The minimum rental period is one (1) month and the first month’s rent must be prepaid in full before the instrument is delivered. Subsequent months are invoiced at net 30 days payment terms. User must pay for the return shipping to Sequoia, and insure the instrument for the full price for the duration of the rental period as well as the return shipping.

If you decide to purchase a new instrument within 90 days after the return of the rental unit you can apply 85% of what you already paid in rental fees towards the cost of the new instrument.

Call for a draft rental agreement.