The Beckman Coulter Model 166 Programmable UV/VIS Detector Module (PDM) is a variable wavelength UV/Vis HPLC detector designed as a part of the HPLC system software. The 166 has low noise and drift over a wide wavelength range. The 166 does not have conventional front panel controls, but is digitally controlled and monitored by either a computer with Beckman Coulter software or a 118, 127 or 128 Solvent Delivery Modules with System Control Center.