Pocket (total dissolved solid) TDS Tester has a platinum sensor and a single point push button calibration mechanism. Its TDS measuring range is low. It is simple to use and offers protection against inclement weather thanks to its waterproof qualities. Fast and accurate measuring results are produced by the typical platinum sensor. A portable TDS meter can be used to measure the total dissolved solid content in aquarium, swimming pool, and waste water.TDS range-0.5 - 100.0 ppm;Calibration points-1 point;Connector-6 pin;Power-3 × 1.5 V “G13A”  for more visit labtron.us