A connection part providing communication between biopharmaceutical containers and/or conduits, includes a connection sheath (32) and two connection skirts (38a, 38b). The connection sheath (32) and both connection skirts (38a, 38b) have resiliency such that the connection part (30), from a disassembled state, is transversely stretchable, at the site of both connection skirts (38a, 38b) thereof, until transversely widened without loss of integrity so as to be made threadable through both collars (14, 24). Then, due to the resiliency thereof, the connection part contacts, with resilient clamping for support and with sealability, the coupled portion of the outer surface of both collars (14, 24). Moreover, from the assembled state, the connection part is transversely stretchable, at the site of both connection skirts (38a, 38b) thereof, until transversely widened so as to be capable of being unthreaded from both collars (14, 24) and thus be converted to the disassembled state.
