Parameters / Specifications Model: 3‑9900.394 Direct Conductivity/Resistivity Module Compatible With: GF Signet 9900 transmitter platform Input Sensor Types: Conductivity and resistivity electrodes (e.g., Signet 2819 to 2823; Signet 2839 to 2842) Function: Converts electrode signals into conditioned output suitable for the 9900 transmitter; enables conductivity, resistivity, and salinity measurement via the 9900 digital inputs Weight: Approximately 0.2 lb (~0.09 kg) in one listing Dimensions: Approx. 4″ × 4″ × 4″ (~101 mm × 101 mm × 101 mm) in one listing Mounting/Format: Module card designed to slide into or attach to the 9900 transmitter enclosure Alternate Part Number: 159 001 699 (associated part number for this module) Application: Water quality monitoring, process analytics, inline conductivity/resistivity measurement in industries such as water treatment, food & beverage, semiconductor, aquaculture, marine, pulp & paper Key Features: Direct interface of conductivity/resistivity electrodes to transmitter Supports salinity measurement when combined with the 9900 digital S3L inputs Simplifies wiring and integration by using a dedicated module rather than separate transmitter for each sensor type