Differentially Pumped Rotary Feedthroughs provides the means of translating rotation through a vessel wall without losing vacuum integrity, enabling probes such as Cryostats to be inserted without effect on the chamber pressure. To maintain the rotary seal, two vacuum ports are mounted to the base flange of the assembly allowing connection to an appropriate independent pumps. These have a 55mm clear bore with coarse and fine control available in addition to motorised options.