The handheld colourimeter range for specific ions use light emitting diodes, an AAA battery and weigh 64 grams. Each unit has been precalibrated to give a digital readout of the ionic concentration for that unit. This is produced by the addition of one or more supplied reagents to the vial containing the sample, placing it in the unit, closing the cover and noting the reading. Multiple tests can be performed quickly, easily and at minimum cost. Ideal for stream watch and general use. Ideal for water studies and environmental testing! Easy to use, more accurate than simple chemical test kits and more economical than professional instrumentation. This handheld checker unit fits in your palm while the large LCD is easy to read. Supplied with 10mL glass cuvette and customer case.