Specification :
Waterproof Eutech TN-100 Turbidity Meter Specifications Principle of Operation Nephelometric non-ratio ( conformance to ISO 7027 and DIN EN 27027) Turbidity Range 0 to 1000 NTU Resolution 0.01 NTU ( 0 to 19.9 NTU) 0.1 NTU ( 20.0 to 99.9 NTU) 1 NTU ( 100 to 1000 NTU) Accuracy ? 2% of reading ? 1 LSD for 0 to 500 NTU ? 3% of reading ? 1 LSD for 501 to1000 NTU Repeatability ? 1% of reading or ? 0.01 NTU No. of Calibration Points 4 points ( automatic) Response Time 1, 000, 000 tests Light Source Infrared-emitting diode ( 850nm wavelength) Special Functions Auto-Ranging; Self-diagnostic Power Requirements 4 x 1.4V batteries, > 200 hours