iMOXS-MFR is a brilliant low-power X-ray source for X-ray fluorescence spectrometers. The maximum high voltage is 50 kV, the maximum power amounts to 30W. High voltage and tube filament current are provided by the control and power supply unit CSU. The X-ray tube resides in a tube housing and can be exchanged rapidly. The tube housing incorporates also a fan for cooling, a filter wheel with four positions, a safety shutter and the attachment for the X-ray optics. In accordance with the requirements iMOXS-MFR can be equipped with a poly- or monocapillary optics.