Abstract: A coupling device (1) for releasably connecting tubular elongate members (4, 5) with improved efficiency. The coupling device (1) comprises first and second end piece connectors (2, 3) which are threadably secured or otherwise attached to connection ends (6, 7) of first and second tubular elongate members (4, 5). First and second end piece connectors (2, 3) are connected by rotating each end piece connector (2, 3) a minimal amount relative to each other, such that the rotation simultaneously locks end piece connectors (2, 3) together and engages mating tapers (31, 32) thus sealing the two end piece connectors (2, 3) and creating a leak proof seal. Coupling device (1) is just as easily disengaged, by rotating the two end piece connectors (2, 3) each in the opposite direction from engagement.