The horizontal and vertical offset mirrors are key optical elements for the SwissFEL ARAMIS Beamline. The offset mirrors for example, are used to deflect and steer the x-ray beam into one of the end stations. As the sample position is about 60m from the mirror, very high demands are put on the mirror positioning system in order to deflect the x-ray beam on to the sample with a micro-meter precision. Therefore precise positioning of the mirrors is required, with specifications to move a load of up to 200kg by steps as small as 0.3µm. Not just the positioning must be precise, but also the stability for short term vibrations and long term drifts must be superior.