Abstract: A connector is provided for making electrical connection between electrical conductors in a first connector casing and electrical conductors in a second connector casing. The first and second connector casings are mutually engageale in one orientation only by relative axial movement. The connector has a first connector assembly (10) at one end thereof and a second connector assembly at the other end thereof, the connector assemblies being engageable with corresponding connector assemblies in other tool bodies. The connector assemblies each have a connector body (11) and a support ring (15) and pins (22, 23, 25) for preventing relative axial and rotational movement between the ring (15) and the connector casing (20), the pins (22, 23 and 25) making no direct engagement with the connector assemblies.