Lutron YK22CT TDS (Total dissolved solids) meters.

CONDUCTIVITY/TDS METER

Model : YK-22CT
* Conductivity : 2 mS, 20 mS, 2 ranges.
* TDS : 2,000, 20,000 PPM, 2 ranges.
* Temp. : 0 to 60.0 oC, oC/oF.
* ATC, RS232, Hold, Record ( Max., Min. ).