What do you guys think of these specs? Is this a good one?
Nutrient Truncheon - EC/PPM/CF Meter

Range: 4 - 52 CF 280 - 3640 ppm (EC x 700); 0.4 - 5.2EC 200-3000ppm(ECx500)
Resolution: 0.1 EC(1 CF); 70ppm 700; 50ppm 500
Accuracy: ±4% of reading
Temperature Compensation: Automatic
Operating Temperature: 0 - 50?(32 - 122?F)
Calibration: Factory Calibrated
Power Source: 3Ã?1.5V Alkaline Batteries (not included)
Auto Sense: Auto On and Auto Off

I'm being honest when I say that this info doesn't mean a hell of a lot to me. I've yet to see someone say exactly what the readings that this thing takes ought to be, and yet I'm told I need one. I mean, how many ppm? What should the EC and CF readings be?