1. Range: 410, 500, 540, 590 and 650nm available 2.test more than 26 Parameters 3. ... 410 - 650nm with optional operating Wavelengths of 410, 500, 540, 590 and 650nm via built-in filters.Display: LCD screenResolution ratio ... ~2.025Total Chlorine0.1~2.026Residual Chlorine0.1~2.0 Sp-1 Portable Colorimeter