Bests & Worsts Reviews from Amazon

First, this device works great and it can't get any easier. I did a few tests and the results were consistent. For quality, ease of use, and 2 years warranty, I believe it deserves 5 stars. The sensors measure the Total Dissolved Solids (TDS), which are the total amount of mobile charged ions, including minerals, salts or metals dissolved in a given volume of water in parts per million (ppm). However, I found out that water from the same source will measure differently when the temperature is different. For example, a room temperature water measured at 150ppm, but 110ppm when cold and 192ppm when hot. I thought its interesting. I like the fact that in the back of this device, they put this sticker so you don't need to memorize anything: How Pure is Your Water? ----------------------- 0-50ppm = ideal drinking water 50-100ppm = carbon filters, springs 100-200ppm = hard water 200-400ppm = average tap water and so on It also has protective cap to cover the sensors (not shown in the picture). It's factory calibrated and is ready to use, but can be re-calibrated with NaCl using a small Phillip screwdriver. Battery lasts for about 1000 hours and the instructions are clear with reference to the website if more information is needed. Overall, it's a 5 star item. No more guessing now!