721N VIS Spectrophotometer has the holographic blazed grating monochromator has the advantages of high wavelength accuracy, good monochromaticity and low stray light. ● Linear regression method and coefficient method are added to the concentration test method. 0% T and 100% T, concentration factor setting and concentration direct. 721G/722G visible spectrophotometer enables quantitative and qualitative analysis of samples within the visible spectrum. It can be widely used in pharmaceutical manufacturing, health, clinical tests, biochemistry, petrochemical industry, environmental protection and quality control fields.