The simplest type of a capillary optics is the X-ray guide, a cylindrically shaped monocapillary. It collimates the X-ray beam and limits the divergence angle at the monocapillary exit to the critical angle of total reflection. In comparison to a pinhole an X-ray guide enhances the intensity on the sample surface considerably. X-ray guides are manufactured with different capillary diameters and capillary lengths in accordance with their application. Additionally they can be equipped by aligned pinholes.