Comparing the SM4 to the SM5

Feature / Capability	SM4 Generation (SM4 / SM4P)	SM5 Generation (SM5A / Custom)
Primary Focus	Underwater & Penetrometer Deployment	Tidal, Above-Water & Deep-Array Monitoring
Standard Sensor Array	36 NIR OBS detectors (1 cm spacing)	48 NIR OBS detectors (1 cm spacing)
Custom Array Extensions	Fixed length	Expandable to 96 or 144 detectors
Daylight / Open Air Use	❌ Blinded by daylight when exposed	Yes (Measures ambient NIR light)
Tidal Zone Suitability	Underwater sections only	Excellent (Seamless air-to-water tracking)
SediSond™ Penetrometer Mode	Yes (SM4P model can free-fall to map density)	❌ High-frequency penetrometer mode omitted
Data Channels per Level	2 channels (180° and 90° reflection)	3 channels (adds ambient NIR light)
Data Visualization	Dual tone false-color imaging	RGB false-color imaging
Additional Sensors	Turbidity (ISO & EPA), Thermometer, 3D Accelerometer	Upgraded ISO Turbidimeter, Thermometer, 3D Accelerometer

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Quick Selection Guide

• Choose the SM4 Series if: You need mobile profiling, want to measure sediment consolidation and impact resistance via free-fall deployment (SediSond™ mode), or require a secure, long-term underwater installation with a traditional screw-down holder tube.
• Choose the SM5 Series if: Your project takes place in tidal flats, beaches, or rivers where the sensor will be exposed to open daylight, or if you need an extended vertical sensor profile (up to 1.44 meters) to track massive sediment shifts.