An extension set for coupling a medical fluid supply tube to the base of a catheter device, said extension set comprising a connector and a base of a catheter device, said base having a circular hub with a circumferential recess defined in a side surface of the circular hub, wherein the connector is rotatably mounted on the circular hub, the connector comprising: a cap having a top surface, a bottom surface, a central region, and a circumferential region; characterized in that the cap defines at least two pairs of slots, each slot extending from the circumferential region of the cap towards the central region and each pair of slots dividing the cap into a plurality of lobes comprising: at least two fixed lobes located on opposed portions of the cap, and at least two resilient lobes, each resilient lobe being separated by a fixed lobe, each resilient lobe including: an outwardly projecting lift tab, an inwardly projecting catch that is configured to releasably engage a circumferential recess defined in a side surface of the circular hub, and at least a resilient region so that each resilient lobe is reversibly deformed and spatially displaced when a force of between about 2 Newtons and about 14 Newtons is applied to its respective lift tab; wherein the connector decouples from the circular hub by lifting at least one lift tab to reversibly displace the resilient lobe and its respective catch radially by deforming the resilient region in order to disengage from the circumferential recess. a cap having a top surface, a bottom surface, a central region, and a circumferential region; characterized in that the cap defines at least two pairs of slots, each slot extending from the circumferential region of the cap towards the central region and each pair of slots dividing the cap into a plurality of lobes comprising: at least two fixed lobes located on opposed portions of the cap, and at least two resilient lobes, each resilient lobe being separated by a fixed lobe, each resilient lobe including: an outwardly projecting lift tab, an inwardly projecting catch that is configured to releasably engage a circumferential recess defined in a side surface of the circular hub, and at least a resilient region so that each resilient lobe is reversibly deformed and spatially displaced when a force of between about 2 Newtons and about 14 Newtons is applied to its respective lift tab; at least two fixed lobes located on opposed portions of the cap, and at least two resilient lobes, each resilient lobe being separated by a fixed lobe, each resilient lobe including: an outwardly projecting lift tab, an inwardly projecting catch that is configured to releasably engage a circumferential recess defined in a side surface of the circular hub, and at least a resilient region so that each resilient lobe is reversibly deformed and spatially displaced when a force of between about 2 Newtons and about 14 Newtons is applied to its respective lift tab; an outwardly projecting lift tab, an inwardly projecting catch that is configured to releasably engage a circumferential recess defined in a side surface of the circular hub, and at least a resilient region so that each resilient lobe is reversibly deformed and spatially displaced when a force of between about 2 Newtons and about 14 Newtons is applied to its respective lift tab; wherein the connector decouples from the circular hub by lifting at least one lift tab to reversibly displace the resilient lobe and its respective catch radially by deforming the resilient region in order to disengage from the circumferential recess.