New TDS & EC Test meter [4in1-TDSmeter] with backlit HD display, a portable device used for reading total solids (EC, TDS, °C, °F) dissolved in a usually water solution. Because dissolved ionized solids, such as salts and minerals, increase the conductivity of a solution, the TDS meter measures the conductivity of the solution and takes the TDS reading. The instrument is already calibrated at the factory, immediate use without any calibration. It is produced by Henan Wanbang EP Tech Co., Ltd among the 5 best producers in the world, distributed in Italy and Spain by CO2 MANIA® that tests its efficiency in Italy. The package includes: 1 TDS&EC 4in1 Pen Test (new reading software) color White 1 transport box 1 CR2032 litium battery instructions