An adapter (10) for connection with a fluid container (4) comprising: an outer housing (16) with a distal end (18), a proximal end (20), and a mostly cylindrical side wall (22) which is extends from the end (18) distal to the proximal end (20)； an inner member (28) comprising a body (34) rotatably inserted into the outer housing (16) and a connector (12) extending from the body (34) configured to connect the adapter (10) to a fluid container (4)； and a first closing arrangement (36) that can be coupled to the body (34) of the inner member (28) and that is configured to restrict the rotation of the inner member (28) relative to the housing (16) in a first direction (TO)； wherein a second closing arrangement (38) can be coupled with the body (34) of the inner member (28) and is configured to restrict the rotation of the inner member (28) in relation to the housing (16) both in the first address (A) as in a second address (B), and where the adapter (10) can pass into: an uncoupled state, in which the first closed arrangement (36) and the second closed arrangement (38) do not are coupled to the inner member (28)； a state of partial engagement in which the first closing arrangement (36) is coupled to the inner member (28)； and a complete coupling state in which the second closing arrangement (38) is coupled to the inner member (28).Un adaptador (10) de conexión con un envase de fluidos (4) que comprende: una carcasa exterior (16) con un extremo (18) distal, un extremo (20) proximal, y una pared (22) lateral mayormente cilíndrica que se extiende del extremo (18) distal al extremo (20) proximal； un miembro interior (28) que comprende un cuerpo (34) insertado de forma rotativa dentro de la carcasa (16) exterior y un conector (12) que se extiende desde el cuerpo (34) configurado para conectar el adaptador (10) a un envase de fluidos (4)； y una primera disposición (36) de cerrado que se puede acoplar al cuerpo (34) del miembro (28) interior y que está configurada para restrin
