This kit requires the use of a CHEMetrics Direct-Readout Photometer or a spectrophotometer capable of accepting a 13 mm Ø round cell. Instrument sold separately. Range: 0 to 20 ppm, Method: Direct Nesslerization, Analysis Time: 2 minutes, Kit K-1533 comes in a cardboard box and contains everything needed to perform 30 tests: thirty ampoules, Stabilizer Solution, 25 ml sample cup, ampoule blank, and instructions.