A connector for use in vacuum system is configured to fluidly connect a first opening formed in a first vacuum chamber to a second opening formed in a second vacuum chamber, the first opening of the first vacuum chamber being provided within the second vacuum chamber. The connector comprises a tube and a biasing O-ring. The tube has an outer wall to define a fluid flow path between first and second ends of the tube. Towards the first end, a sealing portion of the outer wall of the tube is provided. Towards the second end, an O-ring retaining point is provided along the tube spaced apart from the second end of the tube. The biasing O-ring is provided around and tensioned by the outer wall of the tube. The biasing O-ring is moveable along the axial direction between the O-ring retaining point and a sealing position where it seals the connector.