1)7″color LCD touch screen(800*480),Linux OS, function keys or external USB mouse, keyboard,standard RS232 interface, 4 USB interfaces, Ethernet interface,built-in thermal printer or connect external printer 2)Optional measurement methods (End point, Two-point, kinetics, double wavelength, etc.) and calculation methods (factor, linear regression, nonlinear regression, etc.). 3)Store 500 test items and 10000 test results. 1)Absorbency range: -0.3-3.0Abs 2)Resolution: 0.001Abs(display), 0.0001 Abs(internal calculation) 3)Light source: Halogen lamp 4)Wavelength: 340, 405, 510, 546, 578, 620nm + 2 free positions 5)Stability: ≤0.005A/30min