Oakton CON 150 Portable Waterproof Conductivity/TDS/Temperature Meter. The CON 150 meter offers a rugged, waterproof housing with built-in stand at an economical price. The large, three-line LCD lets you view the conductivity or TDS measurement simultaneously with temperature. Convenient auto-ranging and auto-cal functions for one calibration point per measurement range. Select a two-cell probe with a 0.1, 1.0, or 10 cell constant and automatic temperature compensation (ATC). ATC ensures measurement accuracy even in fluctuating temperatures.