The Victoreen® X-Ray Test Device, Model 4000M+ does it all. Simply place the instrument in the x-ray beam, make one exposure, and it serially displays kVp Maximum, kVp Average, kVp Effective, dose, and time. The Model 4000M+ then automatically resets for the next exposure. A CsI photodiode pair provide the kVp measurements through five user-selectable filter pairs. This ensures optimum accuracy over the entire diagnostic range with minimum filtration dependence. Exposure measurements are made with a parallel plate ionization chamber located above the filter wheel.